In the section of the Suganuma clan of the Hankanpu (Genealogy of the Protectors of the Shogunate) written by Hakuseki ARAI, a common saying that Shingen was shot and was injured when approaching the sound of a flute which he heard from inside the Noda-jo Castle, in MIkawa Province when Shinge encircled the castle, is described.
藩翰譜;新井白石著の菅沼氏の項で、武田信玄が、三河国野田城を攻囲中、城中から聞こえる笛の音に惹かれてやってきたところを、鉄砲に狙撃され負傷したという俗説があると記載されている。 - Wikipedia日英京都関連文書対訳コーパス