Hi. You are right, probably a prayer but I suspect other information, maybe the name of the shrine etc. This has probably come out of a shrine that has closed down. I think it is early and has the date 1704. An interesting artifact and I think not common to have in private hands. Yes, not a weapon. I have seen Jpanese statues of Budo myo holding them etc.
I hope Piers or someone else here can tell me about them.
Mark
PS. The Yajiri are a matched set if 12, 2x unusual shaped, sukashi and 10x regular, all signed my Hoki Masayuki, circa late 18th I think. I haven’t done any real study into them as yet.