Samurai retainers who assumed a position with an income to support 10 persons or more were promoted to the rank of guard, which, however, was non-hereditary rank, so that their descendants remained in the previous family rank.
通常、小姓与格や新番格の武士が10人扶持以上の役職に就任すると「一代小番」に昇格することが出来たがこれは本人一代限りの昇格であり、子孫は元来の家格のままであった。