Unification of Japan

On 21 October 1600, two massive armies, an Eastern Army of roughly 88,900 troops led by Tokugawa Ieyasu and a Western Army of about 81,900 troops commanded by Ishida Mitsunari on behalf of the young Toyotomi heir Hideyori, met in dense morning fog near Sekigahara, in present-day Gifu Prefecture, for a battle that lasted only about two hours before Western resistance collapsed. The turning point came when Kobayakawa Hideaki, a nephew of the late ruler Toyotomi Hideyoshi, defected to the Eastern side with 15,000 troops partway through the fighting, shattering the Western Army's position and triggering further defections that left the Western Army with an estimated 30,000 or more dead against roughly 8,000 Eastern Army losses. Victory let Ieyasu seize the authority to redistribute territory across Japan, reassigning roughly 6.8 million koku of land to reward his allies while stripping it from defeated rivals, and in 1603 Emperor Go-Yozei granted him the title of shogun, formally founding the Tokugawa shogunate. The battle brought a definitive end to the Sengoku, or Warring States, period of civil conflict and opened the Edo period, which would keep Japan under Tokugawa rule and relative internal peace for more than two and a half centuries, until 1868.