Prior to the posting as Governor of Mikawa Province, Ieyasu's official rank was a lowly kurandonosuke (assistant official of kurodo) however, although he accomplished the unification of Mikawa, at the time he became the virtual ruler of Mikawa, Ieyasu lacked the necessary rank to be posted as Governor of Mikawa.
三河守を受領する前の家康の官位は蔵人佐という低いものであったが、三河統一を成し遂げ名実とともに三河の支配者となった時点で、三河守受領のために必要な位階を家康は持っていなかった。