I recently obtained a set of glass biconvex go stones of impressive size (11.0mm)--somewhat inadvertently, as they were listed as 8mm, and I wanted them for a travel board! The stones are the typical matte black and shiny white glass, but do not have the "blunted" edge that is typical of Korean manufacture; rather, the overall shape is very similar to my 10.2mm slate & shell set, so it is possible that it is of Japanese origin. The seller claimed they were most likely from China, but in my (limited) exposure to Chinese go goods I have only seen Yunzi glass stones (both black and white with matte finish, and black stones glowing green in strong light), so I do not know if there is production of "non-Yunzi" glass stones in China that mirror the aesthetic of the Japanese stones as well. Thanks for any information you can provide! (Now I have to find a board that will be suitable to these mega-stones, as well as bowls to hold them!! ;-)

Just as a side note: Yunzi ≠ glass, but rather a sintered ceramics

https://en.wikipedia.org/wiki/Yunzi

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