The Abe Clan.

“19 vassals of Lord Hosokawa ask permission to commit harakiri with him, as a demonstration of their loyalty. Only Yaichiemon Abe is refused permission, forced instead into the vassalage of his lord’s successor. Humiliated and derided, Yaichiemon eventually commits harakiri without permission. His eldest son is then punished for Yaichiemon’s suicide, and when he resists, is sentenced to death. The entire Abe clan rebels upon the son’s execution, and the clan is annihilated.” --Alan Poul, Japan Society