It was used as a buoyant body to float the rope when fishing for herring. The size is not uniform because it is blown glass. Japanese Old fisherman's
Restock Set-12 Japanese GLASS Fishing Floats 2.3-2.8 Antique Blue , Green
Glass Float Junkie
Large Vintage Japanese Glass Floats
Riding the Waves: Glass Floats from Around the World
Glass Floats - Nautical Antique Warehouse
Glass Floats – Dorset Gifts
Green Glass Floats
Glass Fishing Floats Art for Sale (Page #2 of 2) - Fine Art America
A true decorative item for in the backyard pond or in your interior! These round glass balls were once used by Chinese fishermen to keep their nets or
Chinese Glass Floats