For much of its history, Japan was divided up between various small states or warred over by factions trying to claim the whole island chain. That changed on this day in 1600, when a general seized power during what many consider the most important battle in Japanese history. His victory resulted in a (mostly) stable political order widely understood as a direct predecessor of the modern nation.
As far back as 250 A.D., much of modern Japan was united under a single emperor, but after some centuries the real power shifted to private armies that the royal court needed to actually exercise any real control over its various regions. Those armies periodically went to war, and the leader of the winning force became a military dictator known as a shogun. A century or so later, they’d be toppled, and the cycle would begin again. Local governments were basically the only stable part of the system and often were de facto independent.
Fast forward to the mid-1500s. A regional governor managed to reunite most of Japan under his control as shogun. When his successor left his infant son in charge after his death, the five nobles meant to serve as regents again started jockeying for power over the now-unified country.
This brings us to 1600, a couple of years after that last shogun’s death. Two groups remained: the Eastern Army, which was ostensibly loyal to the baby shogun, and the Western Army, which was not. On Oct. 21, the two fought a massive battle. Tokugawa Ieyasu, head of the Western Army, was outnumbered, 120,000 to his 75,000, but still managed to win a decisive victory by getting enemy generals to defect. Over the next two and a half centuries, now called the Edo Period, Japan was finally a single, stable nation under the Tokugawas.
