Motives for committing seppuku included oibara (following one's master into death), tsumebara (being forced to commit seppuku as a result of one's professional responsibility or duty) and munenbara (suicide in mortification), as well as being committed by commanders of defeated armies in order to avoid the disgrace of capture by one's enemies, and by commanders of besieged armies in order to have the lives of family members and castle garrison soldiers spared.
切腹の動機としては、主君に殉死追腹（おいばら）、職務上の責任や義理を通すための詰腹（つめばら）、無念のあまり行う無念腹、また、敗軍の将が敵方の捕虜となる恥辱を避けるためや、籠城軍の将が城兵や家族の助命と引き換えに行うなどがある。