When the position for the lord of Amakusa Domain of the Higo Province became vaccant, the cabinet officials of the Shogunate concluded that no other person was more qualified than Tadamasa for the lord of Amakusa.
よって、肥後国天草藩主に欠員が出た折は、幕閣の間にて天草に置くべき人は忠昌を越える者なしと決せられた。