Ishida Mitsunari (石田 三成, 1559 – November 6, 1600) was a samurai of the late Sengoku period of Japan. He is probably best remembered as the commander of the Western army in the Battle of Sekigahara following the Azuchi-Momoyama period of the 16th century. Also known by his court title, Jibu-no-shō (治部少輔).