In the Edo period, the Karo post was inherited by the families of prominent Fudai retainers, or was occupied alternately by powerful Fudai retainers themselves (who had the status to appoint Karo officers).
江戸時代において家老職は譜代重鎮の家臣による世襲、もしくは有力な譜代の家臣（家老職を出せる家格の家臣）による交代制となった。