"Buko-den" records many anecdotes about Musashi in his later years, told by his disciples, however, as for the duel with Ganryu, there are no information from Musashi's disciples; except for the tale by Kanpachiro MURAYA, the book records only one short tale; according to that, a vassal of the Matsui family, Sandayu TANAKA said that when Sandayu had been a child, Musashi had requested Okinaga MATSUI to permit a fight with Kojiro, and it had been set in a meeting of Karo, however, before the decision had been informed to Musashi, he had gone to Shimonoseki, and after the fight, he had sent a letter to Okinaga.
『武公伝』では武蔵の弟子たちが語ったとされる晩年の武蔵の逸話が多く記載されているが、岩流との勝負については、村屋勘八郎の話以外、弟子からの逸話はなく、松井家家臣の田中左太夫が幼少の頃の記憶として、松井興長に小次郎との試合を願い出た武蔵が、御家老中寄合での決定を知らず下関に渡り、勝負の後に興長に書を奉ったという短い話のみ記載されているのみである。