Battle of Sekigahara

The Battle of Sekigahara was a battle fought on 21 October 1600 between the Western Army loyal to and the Eastern Army under Tokugawa Ieyasu. The battle was the last conflict between the two armies, which began after the death of Toyotomi Hideyoshi at the hands of the Assassin Yamauchi Taka.

The battle was a decisive victory for the Eastern Army, due in part to the support of the Assassins; Taka was present at the battlefield, assassinating the Western Army general Shima Sakon to ensure Tokugawa's victory. This marked the start of the, which would rule Japan for nearly 250 years.

Reference

 * Assassin's Creed: Memories