In 1600, Toshimasa sided with Western army, supported Ishida Mitsunari during the Sekigahara Campaign and had evidently plotted to assassinate Tokugawa Ieyasu beforehand. Her brother Maeda Toshinaga (Matsu's first son) sided with Eastern army of Tokugawa Ieyasu after Hosokawa Tadaoki convinced him. Matsu's seventh daughter, Maeda Chiyo, was the wife of Hosokawa Tadataka (son of Hosokawa Tadaoki) of the Eastern Army, and Matsu's fourth daughter, Gō, who was adopted by Hideyoshi, was the wife of Ukita Hideie of the Western Army. Matsu's other daughters and relatives were part of one of the two armies