Yunzi (云子 Hanyu Pinyin: Yúnzǐ ) are Go/Weiqi stones from Yunnan and shortly called Yunzi.
Traditional Yunzi Go stones are half-flat (single-convex or "one-side-convex"). Modern Yunzi are available both half-flat and in lens shape (bi-convex, similar to Japanese go stones).
Chinese players like this for analyzing variations by turning the stones in question upside down. (e.g. cf. with the picture on Weiqi Tiandi, where 杨莲 Yang Lian seems to have turned around all stones)
See XuYing 徐莹 turning around the Yunzi too.
Yunzi have a thickness of 7 to 9 mm and a diameter of 21mm to 22mm. Black stones are slightly larger to make up for an optical illusion. Both are non-glossy with a matte finish.
When Yunzi are held against the light, they will appear dark green or soft white respectively, and show a beautiful translucency.
Modern Yunzi white stones are pure white, while traditional Yunzi white stones have a yellowish tint to them and are known as Old Yunzi, see the upper right picture.
Yunzi playing stones are the official standard of the Chinese Weiqi Academy. They are used in major national and international tournaments.
- The Yunnan Weiqi Factory
- Video from the Yunnan Weiqi Factory (8:30 minutes in Chinese)
Some known sellers outside of China
- Yellow Mountain Imports (US, sells single-convex, bi-convex and Old Yunzi)
- go-spiele.de/ go-games.eu (Europe, sells single-convex and bi-convex Yunzi)
- jeudego.com (Europe French, sells single-convex and bi-convex Yunzi)
- marchand.be (Europe Belgian, sells single-convex Yunzi)
Oiling Yunzi stones
Yunzi stones can be oiled like slate stones. This process gives the stones a light sheen. Other oils can be used as demonstrated by ChiyoDad. To prevent the surface from getting sticky over time, the base oil component should be non-drying.
Air bubbles are normal in translucent sintered products, including Yunzi.
Lead Contamination circa 2007
See ChiyoDad's Blog for information on the problem of lead contamination in some charges of Yunzi produced by The Yunnan Weiqi Factory. If you bought contaminated stones from YMI, it seems you can exchange them. For other vendors, YMMV.
(2015-02-17 20:40 by 18.104.22.168): One should not really put stones in one’s mouth anyway: that is like putting dirty old money in one’s mouth. Who knows how many hands have touched the stone? Plus historical (pre-WW2) stones will more than likely contain lead anyway. Also one should also supervise children and teach them properly to avoid bad habits; even Japanese slate and shell stones can be swallowed, plus shell stones more than likely contain lead too, due to the current state of our oceans.
- Your Go Stones and You: Yunzi, A Journey of Care and Beauty
- Wikipedia article
- Yongzi 永子 http://tchan001.wordpress.com/2012/04/18/go-sighting-32-yongzi/