It it said that Tadatsune and Kameju did not have even one child, and that they therefore tried to have Hisanobu SHIMAZU, his daughter's son, installed as Tadatsune's successor, but failed.
忠恒・亀寿夫妻の間には1人も子が無かったことから外孫の島津久信を忠恒の次の後継者に据えようとしたが失敗したとされる。