In 1600, he sided with Ishida Mitsunari and commanded 6,600 men. His troops fought against Ikeda Terumasa at Battle of Sekigahara (though he saw very little action) and was afterwards deprived of his fief despite sending an apology to Tokugawa Ieyasu. That same year, he had ordered the execution of his elder brother Tsuno Chikatada, who had questioned his right to be Motochika's heir, as ruler of Tosa Province.