Disclosure: I have paid full price for Songyun's products from their amazon storefront. I had an opportunity to help translate some of their English product blurbs; I've not been compensated. I hope this company can provide go equipment to the world in a range of prices.

Songyun's wieqi stones are remarkably similar to the popular Yunzi: single or double convex in different colors and materials. They manufacture ceramic, melamine, and "jizi glaze" stones. It's the jizi that exhibit the signature Yunzi-like translucent green in the black stones.

They have a Chinese website that is presently being redesigned and they are adding new products. https://sywq.cn

Songyun also has a storefront on the amazon. Orders ship quickly from what must be stateside inventory but the current selection is quite limited. https://www.amazon.com/stores/SongYun/p ... f_=ast_bln