However, recently, the theory has become supported strongly as well that this incident was caused due to confrontations between Ieyasu and Nobuyasu, or a father and son, and Ieyasu only asked for Nobunaga's consent (because the legal wife of Nobuyasu was a daughter of Nobunaga).
しかしながら、近年では家康・信康父子が対立したためで、信長には了承を求めただけ（信康の正室が信長の娘であるため）、という説も強くなってきている。