In ninja art books, such as Ninhiden or Shukai BANSEN, there is no description of shinobigatana, but a description that "use thick and wide wakizashi and uchigatana and put them not to break (after the Edo period, common people other than samurai were allowed to carry wakizashi for self defense or revenge if they made registrations at public offices).
忍秘伝や万川集海といった忍術書には忍刀の記載がなく「折れにくいよう重ね厚く幅広い脇差及び錐刀を用いる」という内容が剣術の項にあること（江戸時代以降は武士階級以外の庶民は役所に届出がありさえすれば旅の護身用や仇討ち認可などの理由により脇差までの携行が許された）。