Papers
Working paper PDF
Parties and the military are democracy’s two gatekeepers: when both exclude radicals, democracy should survive. Interwar Japan is a hard case for that expectation. Established parties dominated parliament and the mainstream military kept the radical faction in check, yet democracy failed. I argue radicals circumvented both gates through civic associations that created a grassroots ideological base and coordination networks for violence outside the chain of command, culminating in the February 1936 coup by the Imperial Way faction that precipitated democratic collapse. This strategy worked best in Japan’s northern periphery, where long exclusion from the governing coalition made anti-center agrarian nationalism resonate. Using monthly data on over 4,000 right-wing organizations, I show the May 1932 assassination of the prime minister triggered a sharp surge in the periphery, disproportionately expanding organizations espousing Imperial Way doctrine. Also, periphery-linked personnel connected otherwise separate groups of conspirators in the 1936 coup through shared organizational membership.
Under review PDF
Throughout history, jurisdictional conflict among rival rulers has constrained oppression by enabling subjects to pursue mass exit—often to draw external intervention—instead of directly confronting authority. I document this mechanism in Tokugawa Japan, where a feudal structure of domains with similar institutions but divergent extractive capacity competed for subjects’ loyalty, creating an ideal setting to observe a competitive market for governance. Leveraging newly digitized village-level records of peasant resistance, I show that villages geographically more exposed to neighboring external authority opted for exit over confrontation. I further show that domains facing more intense jurisdictional conflict (i.e., those governing villages more exposed to external authority) extracted lower taxes, net of alternative mechanisms. This relationship, as theoretically predicted, depends on neighboring domains’ labor absorption capacity. These findings highlight mass exit as an active form of popular constraint, surfacing a mechanism long overshadowed by scholarship’s emphasis on direct resistance and notions of passive exit.
Working paper
While scholars broadly agree that feudal orders arose from the limitations of centralized state control, much less is known about the mechanisms through which this process began and unfolded—specifically, who fostered the fragmentation of state power and where it originated. I propose a theoretical framework identifying the conditions under which statebuilders deliberately hollow out their own administrative apparatus by privatizing extraction: granting fiscal immunities in exchange for a share of the returns. I evaluate the model’s implications using the case of early medieval Japan, where varying degrees of feudalization across regions can be systematically observed through estate commendations to the imperial court. Consistent with the theory, I find that estate commendation by emerging local warrior elites occurred most prominently in peripheral regions where central authority was weak but local administrative capacity remained strong.
Work in progress
Although agricultural surplus was vital for early state formation, it also exposed states to external threats. I claim that while surplus itself jeopardized states, the administrative capacity to generate it—specifically hydraulic management—promoted state persistence. Maintaining costly irrigation systems provided rulers with bargaining leverage over both external predators and internal subjects, deterred both invasions and defections, and thereby fostered stable territorial control. I illustrate this argument through a formal model and test it using global data of historical polities since 3400 BCE. Duration analysis shows that states with greater hydraulic dependence, measured by the potential yield gap between irrigated and rainfed farming, tended to endure longer without losing territories, while higher absolute yields accelerated territorial loss. The result was exclusively found in earlier periods, where developing hydraulic systems was more costly. Additionally, polities with greater hydraulic dependence tended to develop more complex social structures.
Work in progress
Social scientists have argued that conflict and military technological innovation fostered the formation of territorial states. While the literature has predominantly examined European history, Japan’s Warring-States Period offers a unique context to test this claim; the island country initially composed by more than 100 autonomous local powerholders (daimyo) was exposed to an exogenous shock of military innovation, an accidental importation of firearms in 1543, after which the fragmented society rapidly transformed into a centralized state under a singular authority. Using original grid-year datasets of battles, castles, and territorial changes, we show (preliminary, descriptive) results suggesting that the technological shock diminished defensive advantage and made economic power better translate into battleground success, thereby inducing small rulers to concede their autonomy.
Other Publications
Pacific Forum Issues & Insights, Vol.22, pp.31–49
Book chapter in 国際関係研究の方法 (University of Tokyo Press, 2021)