At first, kurokuwa were not permitted to adopt a surname or wear a pair of swords except for a short sword for self-defense, but those kurokuwa of fudai in Mikawa Province were allowed hereditary succession and were treated as the lowest rank of Gokenin (shogunal retainers of the Kamakura bakufu) later.
当初は苗字帯刀も許されず、例外的に護身用の脇差だけを持つ事が許されたが、三河譜代の黒鍬については、世襲が許され、後には御家人の最下層格の扱いを受けた。