In the Battle of Sekigahara in 1600, by the order of Ieyasu, he played an important role using especially his brain to suppress local governors of Yamato Province and to disturb the logistic support of the Western Army.
1600年の関ヶ原の戦いでは家康の命を受けて大和の豪族の調略に従事し、西軍の後方攪乱作戦も務めた。