The Japanese name for this item is Senninbari, and this particular one was captured by a former Paramarine who later became a member of the 27th Marines, 5th Marine Division during WW2. The US name for these was “one thousand stitch belts,” and they were a very popular bring back item for US troops during World War Two. Japanese troops wore these under their clothes and around their waists. They were supposed to protect the wearer from injury.
Senninbari generally had one thousand stitches that were done by hand by individuals from their home communities. Each person did one stitch, then passed the belt on to another person. Often, they also had coins stitched to them like this belt does. Sometimes, the thousand stitches were sewn on the belt following a pattern, in order to represent some item or symbol like the tiger shown on this belt. The thousand stitch belt was the physical representation of the community supporting their soldiers.
I have always been a big fan of these belts. There are many variations to collect and I think the ones that have designs on them, like this one with the tiger, have a great look to them.