In 1579, Nobunaga suspected that Ieyasu's legal wife, Tsukiyama-dono, and his heir, Nobuyasu MATSUDAIRA, might have had secret communication with the Takeda clan.
天正7年（1579年）、信長から、正室・築山殿と嫡男・松平信康に対し、武田氏への内通疑惑がかけられた。