However, the relation between Masanori, who was a military expert, and the Bunchi faction (civilian party), which included Mitsunari ISHIDA, rapidly worsened with Japan's Invasion of Korea, and when Toshiie MAEDA died in 1599, he caused incidents with his close friend Kiyomasa KATO, such as, an attack of Mitsunari.
しかし、武勇に優れた正則は文治派の石田三成らと朝鮮出兵を契機としてその仲が一気に険悪になり、慶長4年（1599年）の前田利家の死後、朋友の加藤清正と共に三成を襲撃するなどの事件も起こしている。