To start this thread here is a leather kinchaku drawstring purse set hanging from a stag antler netsuke, with a red glass(?) ojime.
Four braided cords passed through the ojime, but two had snapped. I sourced some black cord (not string) and after a couple of hours restored it to working condition.
Some would say to keep it the way it was found, as is, with frayed and snapped cords. There is no absolutely ‘correct’ answer, but if it’s an easy job, I like to resurrect without damaging what is solid.
1. Photograph original stringing for later referral if necessary.
2. Remove Netsuke by undoing internal knot. Observe how the knot was tied.
3. Find a cord of similar braiding and strength, four strands of which the ojime will accept. (I like to collect natural strings and cords, old and new.)