My father who was in the Seabees and worked on the airbase on Tinian, traded his beer rations to a Marine for a Japanese unit flag, with several dozen Japanese signatures on it, which the marine pulled from a bunker
They likely signed it before their final battle or a banzai charge.
Dad later felt increasingly uncomfortable having it, not having “earned” it and also that it was probably was the last act and will of dozens of men, so he donated it to his local VFW, where its hanging on the wall.
According to the videos I posted those Japanese battle flags had the soldiers name on it plus well wishes from his family and friends
Your father was a great man and I appreciate his sacrifice dearly.