Anybody knows where I can get glass stones of sizes 38 or 40? The biggest I seem to be able to find is size 36. I’ve got some hankering for a slightly larger size, but I also cannot afford clam/shell at the moment. So, glass or yunzi would be a good solution. (I actually like Ing stones’ shape, but not the material so much.)

Thanks!

I've never in 50 years of go playing seen glass stones thicker than 10 mm (size 36?) Glass stones are not luxury items and people who buy them usually want inexpensive bowls for the stones. Stones larger than size 36 require larger bowls which adds to the expense.

There used to be a guy in a Boston area club who had thick stones with somewhat larger bowls. I think altogether, they’d still be less expensive than clam/shell.

(Unfortunately, the guy died a year or so ago and I don’t remember which website he said to have bought them from, but I remember it was one of the regular ones, like Kiseido or Yutopian. He also had a yellow shin-kaya board that folded in half — which I remembering thinking was a bit of a mismatch, quality-wise, to the stones.)

I have. About 10 years ago, we had a Japanese lady staying in town,
and she had these very high-end Japanese glass stones -- I think they were bigger than size 38.
I have no idea where she bought them -- I'm guessing in Japan somewhere -- they were very high-end --
their surface texture was not like the usual glass stones that are smooth and shiny;
rather, they were of a "frosted" texture ( sand blasted ? ), like a frosted beer glass, very fancy --
I've never seen any glass stones, anywhere, Japanese or otherwise, that even came close to hers.

Are you sure they weren’t actually clam shell stones?

Yes.

Here are corean glass stones up to 11mm, diameter 21.5mm:
http://www.hebsacker-verlag.de/go-stones-c-59_3_17.html
Shipping from Germany.
Site is available in english, too.