When Tadateru was born, Ieyasu looked at the baby and because the baby looked very dark and the wide-opened eyes made him look frightening, Ieyasu hated the baby and said to abandon him' (Hankanpu [Genealogy of the Protectors of the Shogunate]).
「世に伝ふるは介殿（忠輝）生れ給ひし時、徳川殿（家康）御覧じけるに色きわめて黒く、まじなりさかさまに裂けて恐しげなれば憎ませ給ひて捨てよと仰せあり」（藩翰譜）。