In the year 1600 Japan was a very different shape than it is today. The country was divided into many small states, each ruled by its own lord, but as tensions grew, these states split their allegiances into a Western and an Eastern Army. The critical battle to win control of the country came at last when these opposing samurai armies met on the fields of Sekigahara, in present-day Gifu Prefecture.
The Eastern Army of warlord Tokugawa Ieyasu emerged triumphant, and for the first time in many years, all of Japan was united under his rule, which would become Japan’s first shogunate. Naomasa Ii was a favored lord of Ieyasu’s, and for his contribution as first into the fray at the Battle of Sekigahara, Ieyasu gave Naomasa Ii the Castle of Sawayama, making him lord of what is now Hikone.