A vassal of the Kuroda family, Minehira TACHIBANA (Hokin TANJI) adapted the information of "Kuroda-han Bugencho" for a Musashi's biography "Heiho Taiso Bushu Genshin-ko Denrai" (Biography of Marvelous Patriarch of Art of Warfare, Esquire Musashi Harunobu) which is also known as "Tanji Hokin Hikki" and "Bushu Denrai-ki;" according to the book, at the Battle of Sekigahara, Musashi served Josui KURODA and fought in Ishigakibaru of Bungo Province (present Beppu City, Oita Prefecture, Kyushu region) against the squad led by Yoshimune OTOMO of the Western army; the book also describes Musashi's anecdotes at the departure and at the attack of Tomiku-jo Castle.
この説に従う黒田家臣・立花峯均による武蔵伝記『兵法大祖武州玄信公伝来』（『丹治峯均筆記』・『武州伝来記』とも呼ばれる）では、黒田如水の軍に属して九州豊後国の石垣原（今の別府市）で西軍大友義統軍との合戦に出陣し、出陣前の逸話や冨来城攻めでの奮戦振りの物語が語られている。