International systems of three great powers, tripolar systems, remain an understudied topic. In this article, I make three claims about tripolarity. First, it is more warlike than either bipolarity or multipolarity. Second, the two weaker poles of a tripolar system usually ally against the most powerful one. Third, when a pole abruptly declines, the two others have a strong incentive to race to prey on it. To demonstrate this, I develop three cases of past tripolar systems rarely discussed: the Epigoni period during the third century B.C. (Eastern Mediterranean system), the period of the Three Kingdoms during the third century A.D. and the period of the late Northern and Southern Dynasties during the sixth century (East Asian system). This study is thus of importance not only for international relations theory but also for understanding current great power relations since today’s world also consists of three poles: China, Russia and the United States.


balance of power, central war, China-Russia-US relations, international system, neorealism, tripolarity


With America’s unipolar moment now behind us, polarity has become once again a hot issue. As international politics moved toward a new structure, competition among great powers now makes the headlines daily. Traditionally, international relations scholars distinguish between unipolar, bipolar and multipolar systems (Waltz 1979: 129–138).[1] Yet, many count in today’s world three great powers: China, Russia and the United States (Allison 2020; Mearsheimer 2019: 8; Simón, Desmaele & Becker 2021: 96). Tripolarity – a system with only three great powers – arguably possesses features distinct from multipolarity.[2] In other words, the current tripolarity is likely to take on a life of its own. Compared to bipolarity and multipolarity, however, tripolarity has received little scholarly attention. This disinterest is understandable since no example of a tripolar system exists in the modern era. In this article, I investigate whether tripolarity will push the international system toward peace or conflict and attempt to bridge this gap in scholarship by describing the rare clear-cut cases of tripolarity in history.

This work not only advances the comprehension of past international systems but also helps explain the relations between today’s three great powers. In opposition to researchers considering tripolarity benign, I show that it is often a violent power structure. Tripolarity is more prone to devastating great power wars than either bipolarity or multipolarity. I reach this conclusion by comparing the outbreak of such central wars throughout three cases: the period of the Epigoni, the Three Kingdoms, and the late Northern and Southern Dynasties. Moreover, I demonstrate through these cases that the two weakest powers show a strong tendency to ally against the strongest. Finally, when a great power collapses under tripolarity, the two remaining poles have a deep-seated interest in seizing as many resources as possible from that declining great power.

This article is organised as follows. In the next part, I clarify a few essential concepts and discuss the distinctive properties of tripolarity. After that, I develop the three main historical cases of tripolar systems, each having a dedicated part. Then, I discuss lessons from the case studies, and I conclude by applying these to the current tripolar relations.

Examining tripolarity

Key concepts

Before diving into tripolarity, I clarify a few definitions and ideas that structure this article. Offensive realism helps explain why the distribution of power and polarity matter (Mearsheimer 2014; also, Labs 1997). States exist in an anarchic world with no superior authority to guarantee their survival. They live alongside numerous other states, all capable of using force and inflicting harm. Hence, they need to wield their resources to defend themselves and maintain military forces. States are forced to care deeply about others’ capabilities since it is impossible to confidently decipher other states’ present or future intentions (Rosato 2015, 2021). The safest course of action is to maximise one’s power to deter or, if necessary, defeat potential aggressors. When one cannot defend itself by its own means, it can try to find like-minded states with which to ally. States must think and act strategically to increase their share of world power, sometimes resorting to war. They all yearn to become the most powerful state since it is the most secure position. States are revisionist when they can and status quoist when they must.

Due to differential growth rates, military prowess and often pure chance, some states will be stronger than others. The top-tier states are called great powers. They possess the most formidable military forces and overwhelmingly determine the trajectory of international politics by making the most crucial decisions regarding war and peace. Therefore, the number of great powers, polarity, matters significantly for understanding the dynamics of the system (Zhang 2023). A great power must

have sufficient military assets to put up a serious fight in an all-out conventional war against the most powerful state in the world. The candidate need not have the capability to defeat the leading state, but it must have some reasonable prospect of turning the conflict into a war of attrition that leaves the dominant state seriously weakened, even if that dominant state ultimately wins the war. In the nuclear age great powers must have a nuclear deterrent that can survive a nuclear strike against it, as well as formidable conventional forces. (Mearsheimer 2014: 5)

Great powers either ‘have a superior military potential, which even with a moderate rate of mobilization generates commanding ready military strength’ or are ‘endowed with a moderate potential in terms of manpower and other resources [but] they mobilize to a greater extent than do states of comparable military potential’ (Knorr 1970: 21). Power is accordingly ‘the inability to inflict … cost on another country’s high-value interests, including territorial integrity and political survival, lives of its citizenry, and economic prosperity’ (Ross 2006: 367). Hence, military might is the ultimate form of power and land forces are the ultimate form of military might. I take navies into account in the three case studies only when it is relevant for understanding the balance of power. One should also examine population and wealth – latent capabilities waiting to be used – because they are necessary inputs for generating military capabilities. States balance foremost against existing military capabilities, but they also consider latent power in their calculations (Levy & Thompson 2005; Mearsheimer 2014: chaps. 3–4). However, if population and wealth are essential to building actual power, they are not power itself (Lobell 2018; Motin 2021).

Defined that way, the sole great powers in today’s world are China, Russia and the United States. Many would disagree with that listing. Some argue that the international system remains robustly unipolar, especially due to America’s technological lead (Brooks & Wohlforth 2023; also, Borges & Lucena 2023). But states need not be even in all indicators to qualify as great powers. In the pre-World War II era, some, like Austria-Hungary and Italy, were universally acknowledged as great powers despite lagging in industrial and technological prowess. The Cold War Soviet Union always remained far behind the United States in numerous economic indicators. Yet, few would deny its polar status because it could muster formidable military forces (Shifrinson 2023, also, 2018: 13–15). Others would call the current power distribution bipolar, with China and the United States as great powers (Maher 2018; Tunsjø 2018). Although China is far above Russia regarding latent power, Moscow manages to keep up thanks to its formidable military, large and autonomous military-industrial complex, and massive nuclear arsenal.

After the Cold War’s end, many saw the European Union, Germany and Japan as potential great powers. But both Germany and Japan failed to live up to expectations. Although they remain economic powerhouses, they do not muster large militaries and nuclear weapons, the earmarks of a great power. The European Union never acquired statehood and remained an international organisation, which, by definition, has no armed forces or unity of command. It is not a great power and is nowhere near becoming one (Mearsheimer 2001: 392–400; Waltz 1993: 50–61). The European construction’s initial impetus came from the overwhelming Soviet threat following World War II (Rosato 2011). Although an impressive case of pooled sovereignty, the EU remains an international organisation formed of independent states still vying for relative gains among each other (Byun 2022; Simón 2017). Without the United States’ reassuring role as a last-resort security guarantor, the EU would probably lose cohesion and fall back to traditional patterns of security competition (Choi & Alexandrova 2020; Joffe 1984; Yost 2002). Hence, the EU is not a pole. China and Russia are the sole states beyond the United States to muster large and well-equipped militaries, survivable nuclear arsenals and defence industries capable of independently sustaining these forces (Motin 2024: 39–45, 71–76). India is likely the closest call (Pardesi 2015), but its dependence on foreign weapons, technologies and natural resources still impedes its ascent to great powerhood.

‘System’ is used here in the neorealist sense of the term. Several states interacting together form an international system. It is a grouping of states that enjoy relations sustained over time and where each could possibly take part in a system-wide general war. This grouping is called a system because ‘the behavior of each is a necessary factor in the calculations of others’ (Bull & Watson 1984: 1; also, Aron 2004: 103; Mearsheimer 2014: chap. 2; Waltz 1979: chap. 5). Thus, such a system is self-contained: it is not a region or a part of a larger system. Indeed, the world has been divided into numerous separate international systems for most of history. The globalisation of the international system would not be completed until the Second Opium War’s end in 1860, which marked the East Asian system’s fusion with the Euro-centric one (Motin 2022c: 138).

This study uses the occurrence of central wars as its yardstick. A central war is a high-intensity conflict including most of the great powers of an international system where the very survival of one or several great powers could be at stake.[3] Such a war has the potential to change the structure (the polarity) of the international system itself. Large-scale military operations are the norm; it cannot be a bushfire war or a succession of skirmishes. The war’s immediate cause or the warring states’ initial intentions do not matter much in defining central wars. Indeed, central wars often start from limited stakes (Copeland 1996: 29; Gilpin 1988: 600–602; Levy 1985: 364–365). Theorists distinguish between peace as the absence of war and stability as the continued existence of the structure (Waltz 1993: 45). Since I am only concerned with the occurrence of central wars, I do not tackle stability and discuss only structural peacefulness.

There is also a more trivial reason for focusing solely on central wars: the poverty of the historical record. The most obvious cases of tripolarity are ancient, and many of the smaller events and details are lost. A study focused on war between great and small powers or limited great power war would risk missing many actual cases and bias the results. The sole possible yardstick for comparison is thus the central war.

Theoretical insights and hypotheses

In this section, I discuss the main features of a tripolar system.[4] Obviously, it is a system where only three states qualify as great powers. Although analysts usually only distinguish between unipolarity, bipolarity and multipolarity, tripolarity has features of its own that deserve a closer inspection.[5]

It is possible to depict tripolarity in a benign light. Wagner (1986) argues that tripolar systems are inherently peaceful. Assume that A, B and C have more or less equal resources. If A seizes B’s resources, C would have no means to compensate for the resulting imbalance of power. Consequently, C has to assist B to prevent A’s victory. In such a configuration, no great power would ever be eliminated. A great power under attack will always receive the unconditional assistance of the neutral third. Since coalitions against the aggressor emerge automatically and quickly, a pole has little incentive to attack another and should be content to keep the status quo. Following this logic, Niou, Ordeshook and Rose (1989: 94–96) add that tripolarity is more stable than bipolarity. In a bipolar system, a weakening pole is unlikely to survive for long since any power imbalance is impossible to correct.

Despite these arguments, the case for warlikeness is more compelling. The number of bilateral relations is three times larger than the single great power relationship characterising bipolarity. Statistically, the more bilateral relations there are, the greater the risk of conflict between two poles (Yalem 1972: 1054–1055). Tripolar systems are the most violent of all since an isolated power unable to find an ally may quickly be attacked and destroyed. Indeed, if the two others form an alliance, there is no way to compensate for the resulting power imbalance. If two poles stop worrying about each other, they can easily free resources to crush the third. Therefore, in a tripolar system of equals, any cooperation between two powers is an existential threat. Tripolar systems come with the same dangers as bipolar systems but not with the same stabilising features. Similarly to bipolarity, the three powers are constantly on alert, eyeballing each other’s moves and ready to react to any crisis. Unlike multipolarity, however, uncertainty about potential threats does not exist. Doubt does not push decision-makers towards prudence and thus does not discourage war. Poles cannot balance threats alone; they must form an alliance or perish. Competition is intense and without the possibility of ever reaching a stable balance of power (Schweller 1998: 40–44). There is no flexibility in the choice of alliance partners. To sum up, tripolarity comes with the great tension of bipolarity but without the flexibility of multipolarity and with a larger number of potential conflicts (Nogee & Spanier 1977: 320–322).[6] Therefore, a straightforward hypothesis appears:[7]

H1. Tripolar systems are more violent than other systems.[8]

Under tripolarity, the two weaker poles have a deep-seated interest in balancing against the strongest; there is no alternative partner to turn to. One could imagine that it is advantageous for a weak pole to bandwagon with the strongest, defeat the remaining pole, and share the spoils. Yet, it is a self-defeating strategy in the long term. The stronger ally will likely take the lion’s share of the spoils for itself because it was the most powerful initially.

Imagine a tripolar distribution of power where A has nine points, B has six points and C has three points. If A and B cooperate to defeat C, A will gain eleven points overall, whereas B will get seven. If A and C ally against B, A rises to thirteen points and C is left with only five points. It means that, in both cases, A creates a large gap of power between itself and the remaining pole, which is then hopelessly outgunned. C would have been better off allying with the other pole against A. If B and C gang up on A and defeat it, B has twelve points, and C gets six. Even if C is still in a worrisome situation, it is better off than if it had joined with A (Schweller 1998: 52–53).[9] Although balancing against the strongest power is not proper to tripolar systems, it deserves to be reemphasised here because it is often lost on pundits expecting Russia to ally with the United States against China.[10] Accordingly:

H2. The two weaker powers will ally against the strongest.

If a great power, for whatever reason, is crumbling down, the two others have a tremendous incentive to intervene and secure as much as possible of that decaying power’s resources. Indeed, if one power succeeds at seizing a large part of the territory or assets of the crumbling pole, the third one will be confronted with an imbalance of power that it will have a hard time reducing. Thus, two poles will tend to prey covetously on the third if it suddenly stumbles. The collapse of one pole heightens the risk of a war with the scavenging two others or among them. Consequently:

H3. When a pole cannot maintain itself and threatens to collapse, the two others will attempt to seize as much of its power base as possible.

Case selection and method

In this section, I explain what cases I chose to study and what cases I discarded. The cases used in this article are far from the traditional cases taken from the modern and contemporary era. This discrepancy stems from tripolarity being a rare structure. The first case is the Eastern Mediterranean system of the third century B.C. known as the period of the Epigoni. The second is the East Asian system of the third century A.D. — the period of the Three Kingdoms. The last one is also the East Asian system, this time of the sixth century, and corresponds to the late Northern and Southern Dynasties era. All these systems were functional international systems with military capabilities concentrated among three poles.

These three cases differ in almost every regard. One is taken from the pre-Christian Mediterranean and the two others from first-millennium China. Everything from geographical arrangement and military technique to culture and political regime differs in each case. These cases were selected on the causal variable, polarity. They belong to the category of most different systems; all variables are different except polarity. If patterns recur while all other potential causal variables differ, we will have some confidence that polarity is the source of these patterns (George & Bennett 2005; Levy 2008: 6–10). For each case, I describe the balance of power and count the occurrences of central war. I then discuss the main features of great power politics to check whether my hypotheses hold up. In no way do I attempt a thick description of the cases. This work limits itself to a focused comparison to gain generic knowledge about tripolar systems (George & Bennett 2005: part 2).

A few potential cases have been discarded. Some describe the Cold War’s second half as a tripolar system, with China, the Soviet Union and the United States as great powers (for example, Nogee & Spanier 1977: 319). Although China was impressive in size and population, it did not qualify as a pole. Even if we overlook the backwardness of its conventional forces, it did not possess an assured nuclear second-strike capability. In the nuclear era, a state deprived of such a capability cannot qualify as a great power. Schweller (1998: chap. 1) identifies Germany, the Soviet Union and the United States as the poles of a tripolar system after 1936 and throughout World War II. Nevertheless, our definition of great power also differs. Schweller’s (1993b: 44) own data concerning military power in 1940 show that the system was closer to multipolarity, with France, Germany and the Soviet Union as leading powers. Even on the eve of World War II, the German military had no apparent edge over the French (Posen 1984: 82–85). Describing the 1930s as a tripolar system is thus far-fetched. Kopalyan, building on Wilkinson, identifies three tripolar international systems (cut into decades) from the ancient Near East, two from India, and three from medieval Europe and the Mediterranean (Kopalyan 2014: 106–107, 118–119, 126–127, 161, 172–173, 2017: 155–165; Wilkinson 2005: 97–99). Nevertheless, their definitions of what makes a pole do not match mine. Wilkinson (2004: 665) codes poles based on their appearance in historical records – following historical narratives. Kopalyan (2014: 41–49) also defines poles differently, including more abstract variables such as political and ideational power.

The period of Indian history known as the ‘Tripartite Struggle’ is sometimes considered tripolar (Majumdar 1977: 306). But the presence of the Arab Sindh as a significant actor makes this case closer to multipolarity. Haas (1970: 105–106) describes a mid-eighteenth-century tripolar system in Hawaii. Isolated in the middle of the Pacific Ocean, this system is at least easy to delimitate. It was, however, closer to multipolarity than tripolarity, with four major powers (D’Arcy 2018: 65; Kuykendall 1938: 30). The actual tripolar period of Hawaiian history (1784–1795) was, in fact, short-lived. Motin (2022a) recorded a few other instances of tripolar systems in history, but all lasted only a few years, making it hard to extract convincing insights. In the following three parts, I develop the above-mentioned three cases.

The Epigoni period

The death of Alexander the Great in 323 B.C. led to the partition of his immense empire. Directly after this dislocation, successor kingdoms engaged in an intense competition to share the spoils and establish their own ruling dynasties over large expanses of territory. Among them, the three most notable were the Antigonids (Macedon), the Ptolemies (Egypt) and the Seleucids. The tripolar period of the Eastern Mediterranean international system starts with the destruction of Thrace by the Seleucids in 281 B.C. It ends with the collapse of Egypt and the start of the Fifth Syrian War in 202 B.C.[11]

Distribution of power

The strongest of the three great powers was Egypt. The Seleucid Empire and Macedon were, respectively, the second and third strongest (Thorne 2012: 118–124). Egypt’s annual revenue was estimated at 14,800 talents, and the Egyptian population was close to seven million (Worthington 2016: 185). When mobilised, its land forces numbered around 70,000–75,000 troops (Eckstein 2006: 82). It also had the most impressive fleet of the ancient Mediterranean, including ninety ‘sevens’ or larger ships – four ‘thirteens’, a ‘twenty’ and two ‘thirties’ (Thorne 2012: 123).[12]

In comparison, the tax revenues of the Seleucids at their height were 11,000 talents annually, and the Seleucid population was around 14 million.[13] Their army was usually close to 30,000–35,000 troops in peacetime and closer to 60,000–70,000 after mobilisation. Although both Egyptian and Seleucid forces contained war elephants, the Seleucid elephant corps was larger, with up to 500 beasts. The Seleucids employed Indian elephants, while the Ptolemies used smaller African elephants. The Seleucids probably did not have any Mediterranean fleet from the 240s to 219; this hints that they were far weaker than the two others on the sea (Grabowski 2011: 118).

Last and least, Macedon’s revenues were smaller by an order of magnitude, with around 200 talents annually, and its population was close to three million (McEvedy & Jones 1978: 125).[14] Its wartime army was also smaller than the two others, with around 40,000 troops. Although the exact strength of the Macedonian navy is unclear, it was more potent than the Seleucids’ navy but weaker than the Ptolemies’.[15]

The period saw fluctuations in the balance of power. The Seleucid Empire weakened markedly during the 240s and 230s B.C. It lost Bactria (Central Asia) and then large swaths of Iranian lands. In addition to the corresponding reduction in land and population, communications with India were cut, resulting in a decline in its elephant force. Moreover, ‘the sudden death of Antiochus II (in 246), the Seleucid defeat in the Third Syrian War (246–241), and the subsequent civil war for the throne (ca. 240–236) severely damaged the reputation and military might of the Seleucid Empire’ (Overtoom 2019: 114–115). Overall, the Seleucid Empire was impressive on paper but failed to expand and entered a slow-motion decline. Most of its resources had to be used for internal stability. Dynastic instability, huge territory to guard and the lack of ethnic unity were a constant source of domestic trouble. The Seleucids managed, although temporarily, to reclaim some territories and stabilise the situation during the 210s and 200s. Macedon was the weakest but paradoxically the most secure, shielded by the Aegean and Mediterranean Seas from the two others. Egypt was arguably strong enough to balance both of them for over seven decades.

Central wars

We can identify four central wars in this tripolar system. First, the Seleucids attacked the Ptolemies but met defeat during what is known as the First Syrian War (274–271 B.C.).

Second, the Seleucids once again attacked the Ptolemies in 260, this time in coordination with the Macedonians. The Seleucids wanted to seize the Ptolemaic possessions in Asia, while Macedon targeted the Aegean Sea. This Second Syrian War ended in 253.

The Third Syrian War (246–241, a.k.a. the Laodicean War) started with a Ptolemaic attack on the Seleucids following court intrigues. The Ptolemies suffered a major naval defeat to the Macedonians at the Battle of Andros in 245, seriously shaking their domination over the Aegean Sea. Whether the Macedonians were acting in coordination with the Seleucids is unclear. Nevertheless, the Ptolemies managed to defeat the Seleucids and take control of southern Asia Minor, Syria and some Aegean territories. The Ptolemaic Empire was then at its peak.

The Fourth Syrian War (219–217) saw the Seleucid Empire invading Palestine and putting Egypt into a difficult situation. Egypt, however, managed to beat the Seleucids decisively at the Battle of Raphia, one of the largest battles of that time.

The Chremonidean War (267–261) figures prominently in this period’s historiography. The Ptolemies fought against Macedon for supporting Greek cities attempting to end Macedonian domination over them. During the 261 Battle of Cos, Ptolemaic naval power took a severe blow, and the Ptolemies failed to knock down Antigonid influence over Greece. Nevertheless, the Chremonidean War was not a central war but a limited conflict, as it did not seriously endanger the survival of either Egypt or Macedon (Hölbl 2001: 40–43; Kohn 2007: 126–127, 154, 547; McKechnie 2017: 648).

Main features

These three great powers all held to the dream of resurrecting Alexander’s gigantic empire. The immediate objectives of the Egyptians were to dominate the Eastern Mediterranean, to preserve their possessions in the Levant and Asia Minor, and to contain Macedonian power in Greece. Macedon’s main goal was to establish dominance over Greece. The Seleucids were mostly interested in pushing the Ptolemies out of Asia. Egypt constantly attempted to prevent the Macedonians (by building coalitions with the Greek city-states) and the Seleucids (by controlling the Levant and Southern Asia Minor) from expanding at its expense. Nevertheless, Ptolemaic control over its Asian and Aegean possessions was never stable, with ebbs and flows (Meadows 2013: 5625).

After a short war in 279, the Seleucid Empire and Macedon recognised each other’s territory and signed an enduring peace. The period saw overall good relations between Macedon and the Seleucids, which had no significant grievances toward each other. In the 260s, a clear axis formed between Antigonus Gonatas of Macedon and his brother-in-law Antiochus I of the Seleucid Empire (McKechnie 2017: 648). Macedon was relatively safe from Egyptian invasion thanks to the Mediterranean Sea and spent most of this period battling against lesser Greek powers. Although Macedonian-Seleucid alliance warfare against the Ptolemies occurred at least once during the Second Syrian War, buck-passing by Macedon seems to have been recurrent. The rich Judaea-Lebanon-South Syria region was the main object of the above-mentioned central wars (Eckstein 2006: 90). Egypt attempted to compensate for its poor relations with the two other poles by cooperating with and financing small powers and rebellious forces hostile to Macedon and the Seleucids (Grabowski 2011, 2012: 83–97).

Eckstein (2006: 104–114) describes the last decade of the third century B.C. as the Hellenistic power-transition crisis. Indeed, Egypt was unable to maintain itself as a great power. In 207, a major rebellion engulfed Upper and Middle Egypt, and the Ptolemies failed to extinguish it. The death of Ptolemy IV in 204 aggravated this civil war. The dynasty and the capital Alexandria fell into turmoil. The Seleucids and the Macedonians soon became eager to exploit this Ptolemaic collapse. Egypt, anticipating such a fate, attempted diplomatic openings towards both Macedon and the Seleucid Empire. However, these efforts were to no avail, as the Macedonians and the Seleucids reached a secret agreement in late 203 to divide Egyptian territories and destroy Egypt’s naval power (Hölbl 2001: 135).

Philip V and Antiochus III hence attacked Egypt in 202, starting the Fifth Syrian War. They hoped to finish off the Ptolemies once and for all and share their empire. Neither the Macedonians nor the Seleucids could allow the other to absorb Egypt in its entirety since it would have resulted in a large imbalance of power. Macedon made the most of the Ptolemaic collapse by building a powerful navy. It then went on a rampage throughout the Aegean Sea and conquered pro-Ptolemaic cities in Thrace. The Macedonians and the Seleucids also invaded Asia Minor (Vaidyanathan 2018: 16–17, 67). By mid-200, Antiochus had taken control of the Levant and threatened to overrun the Egyptian heartland. It seemed then that the Eastern Mediterranean system was destined to become bipolar. The Egyptians, to avoid destruction, and some Greek cities, to escape submission, sent embassies to Rome, asking for help. The Ptolemaic and Greek embassies requesting Roman help and the subsequent Roman intervention against Macedon and the Seleucid Empire were the final acts in the disappearance of the Eastern Mediterranean system.

Three Kingdoms

The East Asian tripolar system of the Three Kingdoms started in 214 with the conquest of the Yi Province by Shu and ended in 264 with the fall of the same Shu. The end of the Han dynasty in 220 is generally used to mark the start of the Three Kingdoms period. As the official end of the Han empire, this date is important symbolically. However, from a power politics perspective, the period began in 214 with Shu’s annexation of Yi Province. It became clear on this occasion that China was counting three rival great powers, namely Shu, Wei and Wu (De Crespigny 2019a: 37).[16]

Distribution of power

The power distribution was unbalanced, with Wei as the first power, Wu the second and Shu the third. Wei was superior in territory, population, wealth and military strength. Its population was close to 35 million, and Wei had around 500,000 troops. It controlled the most productive regions of the Chinese heartland. Its first ruler, Cao Cao, notably succeeded in establishing an efficient taxation system in northern China, further strengthening Wei (De Crespigny 2019a: 33–37; Zhu & Sun 2010: 191).

Wu’s population was close to nine and a half million people. Wu’s geography was both a blessing and a curse. The Yangzi shielded it from Wei’s superior military force, and its proximity to Southeast Asian states allowed for a profitable trade. Nevertheless, Wu’s territory was not a coherent whole since it was formed of two core regions separated by mountains, complicating economic and military activities. The armies of Wu lacked martial efficiency, and the state’s ability to mobilise resources for international competition was limited. Moreover, starting from the 250s, domestic political instability plagued the Wu court. At the time of its destruction in 280, Wu could count on 230,000 soldiers (Crespigny 1991: 17–19, 2019b: 57–60).

Shu had a population of around five and a half million people.[17] It enjoyed a territory which was coherent geographically and protected by mountains all around. It had a productive agriculture thanks to the Yangzi and its tributaries, quality soil and a favourable growing season. Underground assets also boosted Shu’s economy. The wealth of the region and its secure geography compensated to some extent for its demographic inferiority. Shu’s civilian administrative capabilities were limited, and the state was mainly focused on providing for warfare. Shu, immediately before its demise, mustered 102,000 soldiers (De Crespigny 1991: 23; Farmer 2019: 66–67).

Accordingly, the distribution of power during the Three Kingdoms period was unbalanced in favour of Wei. Shu was at first superior to Wu in military power after the conquest of the Yi Province in 214. This power relation changed in 219, with the defeat of the Shu general Guan Yu and the westward expansion of Wu (De Crespigny 2019b: 55–56). From 219 onward, Wei was the first power, Wu the second and Shu the third. Several factors impeded Wei from conquering all of China sooner. Although Wei had a clear lead in military forces, it had to deploy troops in all directions to protect its extended borders. Thus, it had little freedom to focus all of its forces against one adversary at a time.

Central wars

As high-intensity warfare raged almost unabated, this whole period could be considered a single large-scale conflict. Nevertheless, three episodes of central war shine out. First, in 219, Shu attacked Wei and threatened to enter its core territories. After declaring allegiance to Wei in 217 for having a free hand to deal with Shu, Wu attacked Shu and seized its eastern territories. Shu counterattacked in 221 but was beaten the next year. With Shu defeated, Wu felt secure enough to disown its allegiance to Wei. Displeased, Wei attacked Wu and tried to cross the Yangzi without success, withdrawing in early 223. Wei returned to the offensive in 224 and 225 but failed to advance. While Wei adopted a more defensive posture, Shu and Wu’s relations bettered, and they moved against Wei together. In 227–228, they even conducted combined operations, although to little avail. Warfare continued until 234, after Shu failed to break through Wei’s mountain defences.

Second, Wu took the offensive against Wei in 253. Shu also attacked Wei shortly thereafter. After a humiliating defeat at Hefei, Wu stopped major offensives and switched to more limited operations. Shu continued to launch offensives until 258 with no breakthrough and at the price of a great waste of troops and resources.

Third, contemplating that Shu had exhausted itself in continuous warfare, Wei decided to finish it off and mobilised for war. In 263, Wei seized the passes into the border region of Hanzhong and marched on Shu. Wu’s diversionary attacks failed to disturb Wei. Shu finally surrendered in 264 (De Crespigny 1991: 17–23, 2018: xix, 339–341, 2019a: 38–42, 2019b: 62–63; Farmer 2019: 72–76).

Main features

At the very beginning of the period, Shu and Wu were rivals in their longing for territorial expansion. Wu, willing to avoid a two-front war, declared allegiance to Wei in 217. Indeed, since the frontline with Wei had stabilised along the Yangzi River, Wu felt secure enough to declare what was a paper allegiance to Wei. Wei was militarily unable to enforce it on the ground anyway. This allegiance was short-lived, as Wu broke it in 222 after the threat from Shu dissipated. In symbolic terms, a diplomatic alliance between two would-be Emperors of China was hard to justify. Nevertheless, the self-made emperors of Wu and Shu understood that symbolic refinements came second to power politics. From then on, wary of Wei’s superior power, Shu and Wu remained allies, and the overall balance of power varied little (De Crespigny 2018: 300, 2019b: 55–59). From the end of the 220s, Wei-Wu relations became somewhat less competitive, as both sides perceived that decisive military victory was impossible. Indeed, Wu could hide behind the Yangzi, a formidable natural obstacle. On the contrary, Shu had to deal with a land border with Wei, which often moved back and forth, following military fortunes.

Wei was far more powerful than its rivals. Nevertheless, after the death of Emperor Cao Pi in 226, recurrent political instability limited its offensive capabilities and impeded it from throwing in all its weight for more than three decades (De Crespigny 1991: 34). People of that time were aware that Shu and Wu were markedly weaker than Wei and likely could not resist on their own. Their alliance was thought of as a deterrent against Wei. It signalled to Wei that it could not conquer the South piecemeal and forced it into a more defensive posture. Geography also worked to limit Wei’s margins for manoeuvre. Wei chose to play the long game: build up its domestic stability, develop its economy and wait for its hour to come. It finally opted for destroying Shu in the early 260s, after it saw a hole in Shu’s defences and the opportunity for a quick victory. A victorious move would isolate Wu and give Wei the control of the upper Yangzi, a necessary step for supporting a downriver campaign against Wu and annihilating it quickly (Killigrew 2001: 98–110). With the fall of Shu imminent, Wu scrambled its forces to eastern Shu to seize as much territory as possible before Wei forces occupied it. But the resulting imbalance of power was now impossible to correct.

Late Northern and Southern dynasties

The last tripolar system formed after the northern Chinese Wei Empire collapsed in 534 and split into two separate states in 535. It was composed of Eastern Wei (called Northern Qi after 550), Liang (Chen after 557) and Western Wei (Northern Zhou after 557). This system came to an end in 577 when Northern Zhou conquered Northern Qi. Tripolarity followed a long bipolar stalemate between Northern Wei and the Southern dynasts. This period too was plagued by more or less constant warfare, as the three great powers were all willing to reunify China after more than three centuries of fighting.

Distribution of power

Eastern Wei/Northern Qi was the most powerful of the three states in all regards. It was populated by around 20 million inhabitants and had close to 200,000 troops. It was a territory of fertile lands. Nevertheless, as the quality of the leadership and military readiness declined in the 560s, late Qi was somewhat weaker than at the beginning of the period (Dien 2019a: 184–193; Eisenberg 2008: chap. 4).

Liang/Chen’s population was close to 11 million, and it could count on nearly 100,000 troops. Starting with a civil war in 548, Liang experienced a stiff decline, which allowed Qi and especially Western Wei to take large swathes of land away from it. In 555, the newly installed Chen regime managed to stop the collapse. Nevertheless, it never recovered to its former level (Chittick 2019: 265–269; Graff 2002: 132).

Western Wei/Northern Zhou had a population of seven million. Zhou’s military rose from around 50,000 troops in the 550s to over 100,000 in the 570s. In 575, while preparing for an assault on Qi, it could count on 170,000 troops. This expansion is explained in part by the manpower obtained through territorial conquests. It is also due to structural reforms that boosted both the size and the quality of its forces (Graff 2002: 109–114).[18]

At the beginning of the period, Eastern Wei was clearly the leading power, with Liang as number two and Western Wei as number three. While Western Wei was undertaking self-reinforcing reforms, the uprising of Hou Jing in 548 marked a major weakening of the South. This weakening is also explained by a gradual decline in military readiness and the low mobilisation capabilities of the state (Chittick 2019: 239–240, 264–265; Dien 2019b: 215–216). This allowed Northern Zhou’s rise as the second power of the system. Although Western Wei had a harder time than the East in mobilising troops during the earlier part of the period, it became more and more capable of raising armies of over 100,000, thus progressively closing the gap. From the 560s, poor leadership began to cripple Qi’s military readiness. The military power gap between Qi and Zhou was almost closed by the end of the period.

Central wars

At the beginning of the period, episodes of warfare were interspersed by short truces. Two central wars are then visible. The first one started in 547 when the governor of the southernmost region of Eastern Wei, Hou Jing, revolted and invited Liang to enter his realm.[19] After pushing back the Liang invasion, Eastern Wei turned against Western Wei in 548, which had also tried to benefit from the rebellion to make territorial gains against its eastern neighbour. Western Wei then marched into Liang in 550 and made significant territorial advances against a Liang plagued by domestic instability. Western Wei launched its final assault on Liang in late 554. After the capital Jiangling fell in 555, a Liang rump state was established, while most of Liang was taken over by the new Chen dynasty. Qi invaded Liang’s remnants in 556, but this endeavour ended in a terrible defeat, marking the end of this central war.

Second, Northern Zhou launched a probing attack against Qi in 575 but was repulsed. Nevertheless, it kept preparing, and the second and final central war of the period started in 576. Northern Qi was soon overrun and disappeared in 577. Chen took the opportunity to seize as much territory as possible from Qi, although these conquests were short-lived (Chittick 2019: 270; Dien 2019a: 196–199, 207–208, 2019b: 221–223; Wallacker 1971: 615).

Main features

This tripolar system is the closest to a war of all against all. The two weaker states did not openly ally against Eastern Wei/Qi. Nevertheless, Western Wei/Zhou and Liang/Chen fought less against each other than against Eastern Wei/Qi. Indeed, the 547–556 central war is the only instance of intense fighting between the two. In the late 540s–early 550s, as the system threatened to return to bipolarity, the two northern states attempted to conquer as much of the falling Liang as possible before the other could take a decisive advantage. Aside from central wars, skirmishes and confrontations happened foremost between Western Wei/Zhou and Eastern Wei/Qi. There was an implicit agreement between the South and the Western Wei/Zhou about who the main threat in the system was.

The patterns of conflict evolved with the balance of power. Until about 560, the East was on the offensive and the West on the defensive. Mountainous terrain helped Western Wei significantly against its stronger neighbour. Nevertheless, the relationship changed due to Qi’s dynastic weaknesses and Zhou’s reinforcement, and the East shifted to a more defensive posture. Qi made openings toward Chen, which led to a decade of peace. In 568, it also used diplomacy to better its relations with Northern Zhou, to little avail. In the early 570s, Zhou, while preparing for the final confrontation with Qi, freed a number of Chen prisoners to ameliorate the relations with the South. Noticing Qi’s internal distress, Chen took territories from it in 573 (Dien 2019a: 202–206, 2019b: 210–211, 230; Eisenberg 2008: 103–104). When the final blow came to Qi in 577, Chen tried to seize more lands but was pushed back by the triumphing Zhou. A few years later, with the additional resources of the Zhou state, the new Sui dynasty was quick to destroy Chen and reunify China.



These three cases represent 174 years and nine central wars overall. That is a rate of a central war every 19 years.

In the Epigoni case, the power distribution corresponds to Egypt as number one, the Seleucid Empire as number two and Macedon as number three until the very end of the system. This configuration witnessed four central wars. Three were started by the Seleucids and one by the Egyptians. This represents a central war every 20 years.

The case of the Three Kingdoms started with Wei as number one, Shu as number two and Wu as number three. Shu initiated the first central war under that configuration. From 219 on, Wei was stronger than Wu and Wu stronger than Shu. Wu and Wei then initiated one central war each. Central war broke out on average every 17 years.

Until 548, the case of the Northern and Southern Dynasties had Eastern Wei as the strongest power, Liang as the second and Western Wei as the third; Liang started one central war. The system then moved to Northern Qi being the first power, Northern Zhou being the second and Chen being the third. The last central war occurred under this distribution of power at Northern Zhou’s initiative. This means a central war every 22 years.


In this section, I first demonstrate the validity of the three hypotheses. I then elaborate on a few other points related to the case studies.

H1. Tripolarity is far more violent than bipolarity and multipolarity. Motin (2020), building on Levy’s (1985) data, finds that multipolarity witnesses on average the outbreak of a central war every 39 years, while bipolarity produces a central war every 35 years.[20] With a central war every 19 years, it is apparent that tripolarity is far more violent than multipolarity.

H2. A clear pattern of amity between the two weaker states and enmity between these two weaker states and the stronger pole is visible. The Macedonians and the Seleucids were allied throughout almost the whole period. Except for the very first years of the Three Kingdoms case, the same is true for Shu and Wu. Sixth-century East Asia did not see an open alliance between Western Wei and Liang. When Liang collapsed, Western Wei attacked it to seize as much territory as possible. If one looks at the whole period, however, both states were more often in conflict with Eastern Wei/Qi than with each other. They clearly refrained from attacking each other until after Northern Qi was defeated.

H3. In the three cases, a striking pattern appears four times: when one of the poles seems about to collapse, the two others rush to seize as much of its territory and resources as possible. ‘Competitive preying’ happened in 264, when Wu, failing to reinforce the collapsing Shu, tried instead to seize its eastern territories before Wei did. It also happened after 548, when the two Wei states preyed on the crumbling Liang dynasty. When Chen realised that Northern Qi was collapsing under Northern Zhou’s offensive, it tried to seize some Qi territories, with little success. ‘Cooperative preying’ is visible in the late third-century B.C. Mediterranean system, when Macedon and the Seleucid Empire agreed on sharing Egypt.

We can also make several other observations. A surprising and unexpected result is that the number two states are especially prone to initiate central wars. Out of nine wars, seven were initiated by the number two, while only two wars were started by the number one power. I propose a simple explanation. The stronger side, since it is alone, wants to eliminate the two others. Nevertheless, it can be afraid to reinforce the other great powers’ cooperation if it behaves too aggressively, as it would prefer to pick one enemy at a time. The weakest state has no interest in seeing any of the other two destroyed, as there would be a massive imbalance of power with the surviving pole. In the three cases, no central war was initiated by the weakest power. This is embodied by the behaviour of Macedon, which acted far less aggressively toward Egypt than the Seleucid Empire did. The number two state is more bellicose because it has a strong incentive to destroy the lone number one power and become hegemonic, and it knows that number three is unlikely to ally with number one for fear of breaking the balance.

The birth and death of tripolar systems also deserve a few lines. Gilpin (1981: 91) expects bipolar systems to naturally evolve into tripolar systems. Nevertheless, only my third case appeared from a bipolar system, while the two others came out of multipolarity. On the other end, Waltz (1979: 163) writes that the fate of tripolarity is to turn into bipolarity, as two powers should be quick to gang up against the third one and share the spoils of the conquest. Tripolar systems tend indeed to be short-lived and violent. There is a clear tendency to evolve toward either bipolarity or unipolarity depending on the initial distribution of power and the dividing of the spoil. Had the Romans not entered the Eastern Mediterranean, the system would have turned into a bipolar one centred on Macedon and the Seleucid Empire. Wei’s victory over Shu overthrew the balance of power and made possible the swift annihilation of Wu. Northern Zhou, although initially weaker than Northern Qi, managed to absorb its huge resources and soon turned the system to unipolarity.

Conclusion: Tripolarity in our times

Is the above discussion relevant to the current tripolarity? I do not put an equal sign between these long bygone eras and nowadays: everything does not revolve around polarity. Military technique has changed quite a bit since the Ptolemies and Cao Cao. China, Russia and the United States have to deal with their share of potent regional powers. That said, structural pressure works the same regardless of the epoch or the situation’s specificities. Tripolarity is a volatile power structure where relations between the leading pole and the two others are usually venomous.

For example, tripolarity is already affecting arms control agreements. The United States left the Intermediate-Range Nuclear Forces Treaty in 2019 and withdrew from the Treaty on Open Skies in 2020 because of Russian violations. In early 2023, Russia suspended participation in the last remaining nuclear arms control agreement, START. Moscow then withdrew its ratification of the global treaty banning nuclear weapons tests in November 2023. A few days after, it pulled out of the Treaty on Conventional Armed Forces in Europe, and the United States suspended its participation in it in response (Cole 2021; Hennigan 2023b; Osborn 2023; VOA 2023). Tripolarity complicates arms control and confidence-building measures, while bipolarity simplified them. Conciliating the interests of three powers and enforcing compliance is more difficult.[21] This is visible when US officials stress the need to move beyond bilateral agreements with Russia to include China as well (Allison & Herzog 2020; Barrie, Elleman & Nouwens 2020; Hennigan 2023a). Furthermore, tripolarity encourages increasing one’s nuclear arsenal. A pole could fear that a nuclear exchange with another will leave its nuclear arsenal too depleted to deter or defeat the third, increasing the incentive to stockpile weapons.

Some commentators suggest that the United States played the Russian card against China the same way that it played the Chinese card against the Soviet Union during the Cold War (Crawford 2021; Ferguson 2020; Kaplan 2017; Kupchan 2021; Miller 2020). I argued above that the number two and three powers tend to ally against the number one because if the system evolves into bipolarity, the weaker pole will likely face a dangerous gap of power with that leading state. China and Russia thus have a clear impetus to work together against the United States to maintain a balance of power. In the long run, staying on Beijing’s side makes good sense for Moscow, and it has no reason to jump on the American bandwagon. If China somehow collapses, Russia would still have to face US presence in Europe while it would also need to deal with a mainland Asia now opened to US influence, with no great power ally available. Oppositely, if American power was to recede markedly, the Kremlin would face a dominant China in East Asia, but its position would be strengthened in the Middle East, in the Caucasus and most importantly in Europe, where it would be near hegemonic. Indeed, Sino-Russian relations have been overall excellent in recent years, and both share a willingness to roll back US power (Blank 2020; Korolev 2019; Rolland 2019; Yoder 2020). Unsurprisingly, China has proven eager to bolster Russia’s war effort in Ukraine to distract and exhaust the United States (Düben & Wang‑Kaeding 2023).

The strongest counterargument against this conclusion is geography. Because Russia has a long border with China while the United States is an ocean away, it should be more concerned about China’s rise than about distant America. Nevertheless, the Russians should know that reality better than anyone else and yet, they are still on the Chinese side of the fence. There is no sign that Russia is about to abandon ship and join a balancing coalition with America. Although Russia directly borders China, the European core of the Russian state is out of reach; Moscow is indeed at a distance of a few thousand miles from China.

States mainly focus on the balance of land forces. Hence, geography and distance matter tremendously in identifying threats (Boulding 1962; Porter 2015). Even though Chinese ground forces are modernising, they have lost a great part of their manpower in the process and Beijing has mostly channelled its money into its navy to defy US presence in the Western Pacific. A continental-scale attack to march on Moscow is a nonstarter. Russia is well aware that Asian states cannot threaten its survival in the way European states can. The only Asian force ever to invade European Russia was the thirteenth-century Mongolians. Meanwhile, the list of European powers that rampaged Russia is far more impressive. During the interwar period, before Germany rebuilt its military power, Japan was arguably the single most powerful threat to the Soviet territory (Haslam 1992: chaps. 1–4).[22] Yet, the Soviet Union kept maintaining most of its military on its European side.

Nowadays, Moscow is still primarily concerned with European affairs and is laser-focused on the balance of forces with NATO (Cottey 2022; Haynes 2020; Korolev 2016; Marshall 2015: chap. 1; Ross 2020). Russia constantly points to the Alliance as its main opponent in its strategic documents (Brzozowski 2020). It worries that the expansion of NATO’s infrastructures could allow the United States to deploy troops to its borders on short notice (Tass 2018). The Kremlin has a deep-seated interest in expanding westward and rolling back US influence in Europe. Accordingly, Washington wants to keep Europe’s resources and wealth out of Russia’s grip (D’Anieri 2019: 111–112; Popescu 2019: 385–388; Tabachnik & Miller 2021). The ongoing war in Ukraine is unlikely to allay these fears anytime soon.

A state that is the sole great power (like Russia) in its home region (here, Europe) tends to focus on its bid for regional hegemony and invests little energy in the affairs of other regions (Elman 2004; Motin 2022b, 2024: 39–45). Even if the United States could somehow make a grand bargain with Russia and abandoned Eastern Europe to its fate, Moscow would still be too preoccupied with European affairs to join a balancing coalition. If NATO retracted to its 1990 borders, the Russians would make a quick job of Belarus and Ukraine and establish hegemony over Eastern Europe. West European states, primarily France, Italy, and Germany, would be forced into a crash-course balancing effort to contain Russia, while Moscow would focus on putting Berlin, Paris, and Rome out of business. Hence, Russia would grow in strength but still have more interest in Europe than in East Asia.

I argued that central wars occur more often under tripolarity than in other configurations. The two weaker great powers of the system can be expected to ally against the stronger one. In the case studies, the same pattern repeated several times: when a pole weakens considerably in a tripolar system, the two others have tremendous pressure to move in and take over its resources. That said, much work remains. Further studies examining forms of competition other than central wars are needed. Research on the foreign policy decisions of both great and small powers under tripolarity would also prove valuable. Finally, more comparisons between tripolar, multipolar and bipolar cases could enhance our comprehension of today’s environment.

The current tripolarity will likely be unstable, and the Sino-Russian rapprochement is here to stay. If one of the three great powers suddenly crumbles, the two others will probably take advantage of the situation aggressively. Chinese, Russian, and also Asian and Western decision-makers should bear this pattern in mind and act accordingly if the day comes that China or Russia suffers a crisis or a sudden collapse. A new bipolar system with a Russian pawn in Beijing or a Chinese protectorate over Russia would serve no one’s interests. How the international structure will evolve in the coming decades is hard to divine. The rise of India could result in a multipolar system. China or Russia could stumble, sending the system back to bipolarity. Both of them could also face such internal difficulties that unipolarity makes a comeback. Until such a day comes, maintaining the tripolar peace will remain a daunting task.


Dylan Motin is a doctoral candidate majoring in political science at Kangwon National University. He is also a researcher at the Center for International and Strategic Studies and a non-resident fellow at the European Centre for North Korean Studies. He is the author of Bandwagoning in International Relations: China, Russia, and Their Neighbors (Vernon Press, 2024).



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[1] Kegley and Raymond (2020: chap. 7) sum up well the debate on current polarity. ‘Unipolar moment’ is from Krauthammer (1991).

[2] The seminal study concerning tripolarity is Schweller (1998). Other works are Haas (1970), Kegley and Raymond (2020: 149–150), Nogee and Spanier (1977), Wagner (1986), and Yalem (1972).

[3] Survival has here two meanings: the continued existence of the state itself and the possession of enough capabilities to remain a great power.

[4] Some focus on ‘strategic triangles’; although they have similarities, triangle and tripolarity are distinct. Triangles can form between all states and under any power configuration while tripolarity strictly designates the great power structure of the international system. The seminal work on triangles is Dittmer (1981). See also Lee, Muncaster and Zinnes (1994) and Woo (2003).

[5] For bipolar and multipolar systems, see Motin (2020: 101–103). For unipolarity, see Hansen (2011) and Monteiro (2012: 13–36). For a criticism of the concept of polarity, see Brooks and Wohlforth (2016: 7–15) and Schweller (2010). Some believe in the advent of overlapping power structures, such as Huntington’s (1999) ‘uni-multipolarity’.

[6] Saperstein (1991: 71), through mathematical modelling of the different systems, also finds tripolarity more violent than bipolarity.

[7] Schweller advances more precise hypotheses concerning specific distributions of power. Nevertheless, he uses states’ intentions as an independent variable, while I do not. Moreover, my cases offer only one type of tripolar power distribution (A stronger than B, B stronger than C), while Schweller (1993a: 77–81) identifies four.

[8] This does not include unipolarity because, by definition, there can be no great power war.

[9] C is thus the most interested in the survival of the tripolar system, since it would have to cope with a large imbalance of power if the system moves to bipolarity.

[10] I develop this in the last part of the article.

[11] This chronology follows Eckstein’s (2006: chap. 4).

[12] A seven is a ship with seven men to each oar. Ptolemy IV even launched a ‘forty’, propelled by 4,000 oarsmen (Heinritzi 2017: 50).

[13] Aperghis (2004: 57) gives a range of 12 to 16 million, with a flip to 9–12 million during the 230s and 220s due to territorial losses, while McEvedy and Jones (1978: 125) give Alexander’s Empire in Asia at 13.5 million people. I accordingly settled on the 14 million figure. Populations and revenues of Egypt and the Seleucid Empire are discussed at more length by De Callataÿ (2004).

[14] The regular revenues discussed here do not account for spoils of war and miscellaneous revenues.

[15] Sea power is touched on in more detail by Morrison (2016: chap. 2).

[16] Wei (a.k.a. Cao Wei) was formally proclaimed in 220, Shu (a.k.a. Shu-Han) in 221 and Wu in 222. For simplicity, I use these names all along.

[17] Population numbers are calculated based on a total Chinese population of 50 million people (De Crespigny 1991: 14–15).

[18] I deduced Liang and Western Wei’s population from Eisenberg (2008: 93).

[19] For the story of Hou Jing and his revolts, first against the Eastern Wei and then against the Liang, see Pearce (2000).

[20] I use the collapse of the Habsburg empire in 1556 as the starting year. Levy (1985: 372) identifies ten central wars between 1556 and 1945. Motin (2020: 114–115) bases his study on six historical cases of bipolarity covering 1015 years of data. If one uses instead Motin’s (2022a: 192) larger dataset, the discrepancy with bipolarity (one central war per 31 years) is slightly smaller but far larger with multipolarity (one central war per 85 years).

[21] Yalem (1972: 1061) made this point during the Cold War. See also Gibbons and Herzog (2022) and Miller (2020: 20–24).

[22] Germany’s army was smaller than Japan’s from 1920 up to the mid-1930s (Rasler & Thompson 1994: 198).