Kamakura shogunate

The stability of this bizarre dual-government was quickly put to the test. Sensing weakness after the end of the Minamoto line, Emperor Go-Toba launched an armed attempt to restore direct imperial authority in the Jōkyū War of 1221. The rebellion was swiftly crushed, cementing the shogunate’s supremacy over the Kyoto court. To formalize their rule and provide a stable framework for the warrior class, the Hōjō promulgated the Goseibai Shikimoku in 1232, a pioneering legal code that served as the bedrock of samurai law for generations. They established a court of appeals (Moncho-jo) and reorganized the central administration around a council of state, the hyōjōshū. For five decades, this administrative machinery operated with quiet, bureaucratic efficiency, adjudicating land disputes and maintaining a fragile peace across the provinces.

This internal peace was shattered in the late thirteenth century by a threat from across the sea. Having conquered much of mainland Asia, the Mongol emperor Kublai Khan turned his attention toward the Japanese archipelago. Recognizing the danger through a cooperative relationship with Korea—whose court, though garrisoned by Mongol occupiers, managed to smuggle intelligence to the Japanese—the shogunate was well-prepared. When Kublai’s envoys arrived demanding submission, the Hōjō leadership summarily rejected the demands. In 1274, a joint Mongol-Korean force of roughly 40,000 men landed at Hakata Bay. Though the defenders were outnumbered, they held their lines against the unfamiliar weapons and tactics of the continental army. Sensing an approaching storm, Korean mariners advised the Mongol commanders to retreat to their ships; the resulting typhoon devastated the fleet, destroying a third of the invasion force.

Kublai Khan remained undeterred. When his ambassadors returned to Japan to demand tribute once more, the Hōjō executed them. Expecting a second assault, the shogunate mobilized the defense of the western provinces on an unprecedented scale. They constructed a massive stone wall along the shores of Hakata Bay, reorganized garrison rotas, and built a fleet of small, agile boats to harass the Mongol ships. When the armada arrived in 1281—a colossal force of 150,000 men comprised of Mongol, Korean, and Chinese troops, including conscripts from the recently defeated Southern Song dynasty—they found a heavily fortified coastline. For seven weeks, the invaders tried to establish a secure beachhead in Kyushu but were repeatedly repulsed by the samurai. Once again, nature intervened. A massive typhoon struck the coast over a two-day period in mid-August. Thousands of invading soldiers who could not board the retreating ships in time were left stranded on the beaches and slaughtered by the defenders.

Though the "divine wind" (kamikaze) had saved Japan from foreign conquest, the victory carried the seeds of the shogunate's destruction. For two decades, the Kamakura government remained on a high state of military alert, draining its treasury to maintain defenses against a third invasion that never came. More critically, the nature of the conflict broke the traditional economy of samurai warfare. Typically, Japanese warriors expected to be rewarded for their military service with lands seized from defeated domestic enemies. Because the defensive war against the Mongols yielded no new territory or loot, the shogunate had nothing to distribute to the thousands of warriors who had mortgaged their estates to fund their armor, horses, and retinues. Discontent festered among the provincial samurai, who felt abandoned by the distant chancellery in Kamakura.

The collapse, when it arrived, was swift and total. In 1331, Emperor Go-Daigo took up arms in an attempt to overthrow the Hōjō regency. Though initially defeated and exiled to Oki Island by the shogunate’s formidable general, Ashikaga Takauji, the emperor’s cause found a sympathetic ear among disillusioned provincial warlords. When Go-Daigo escaped exile, the Hōjō sent Takauji to Kyoto to suppress the rebellion once more. However, recognizing the deep-seated grievances of the warrior class, Takauji switched sides, turning his armies against the shogunate’s forces in Kyoto in support of the Emperor. Simultaneously, another loyalist warlord, Nitta Yoshisada, launched a direct assault on Kamakura itself. Caught between provincial rebellion and internal betrayal, the Hōjō regency dissolved in a final act of mass suicide. In 1333, approximately 870 members of the Hōjō clan, including the final regents, ended their lives at their family temple of Tōshō-ji.

The fall of Kamakura marked the end of Japan's first warrior government, but not the end of military rule. Though Emperor Go-Daigo briefly re-established imperial authority, the restoration was short-lived. In 1336, Ashikaga Takauji seized control for himself, founding a new shogunate and ensuring that while dynasties and capitals might shift, the era of the samurai would endure for centuries to come.