Ieyasu's eldest legitimate son Nobuyasu MATSUDAIRA killed himself by order of Nobunaga ODA, and the second son Hideyasu YUKI was adopted by Hideyoshi TOYOTOMI (and later by Harutomo YUKI), so the third son Hidetada TOKUGAWA was determined early on as his successor, but there was an episode that Ieyasu had a question about Hidetada's capability because he arrived late in the Battle of Sekigahara, and Ieyasu asked his vassals, including the fourth son Tadayoshi MATSUDAIRA, who was the appropriate successor.
家康の嫡男松平信康は織田信長の命で切腹させられており、次男の結城秀康は豊臣秀吉（後に結城晴朝）の養子に出したため、後継は早くから三男の徳川秀忠に定めていたが、関ヶ原の戦いでの遅参など、資質に疑問を持った家康が四男松平忠吉も含め、功臣たちに後継者は誰が良いかを尋ねたという逸話が伝わっている。