Between July and August of 1507, Masamoto HOSOKAWA was killed by men of his adopted child Sumiyuki HOSOKAWA, and a fight broke out between Sumiyuki and Masamoto's another adopted child Sumimoto HOSOKAWA, so Yoshinobu guarded the Imperial Palace with about 30 soldiers under his command.
永正4年（1507年）6月、細川政元が養子細川澄之の手の者に殺害され、澄之ともう一人の養子細川澄元との間で合戦が起きると、義信は30人程の手勢で禁中警護に当っている。