If the shogun family had no inheritors, it was supposed to adopt a son from the Owari or Kishu families; the shoguns from Yoshimune TOKUGAWA, the eighth, through Iemochi TOKUGAWA, the fourteenth, came from the Kishu family.
将軍家に後嗣が絶えた時は、尾張家か紀州家から養子を出すことになっており、8代将軍徳川吉宗から14代将軍徳川家茂までは紀州家の血筋である。