Go equipment
The oldest known surviving Go equipment is a board carved from rock that dates from the Han dynasty in China.
The Go board, called the goban 碁盤 in Japanese, is the playing surface on which to place the stones.
Wooden boards subjected to excessive humidity or a large variation of humidity or temperature may be affected by discoloration, warping, cracking, woodworm, or mold, and prolonged exposure to sunlight can bleach the board.
Boards transported between climates with significantly differing humidity levels may be subjected to warping or cracking due to rapidly changing moisture content in the wood.
Go stones, or go-ishi 碁石,棋子, are round objects placed on the board.
Thick slate and shell stones can last for generations, slowly becoming thinner from handling, and gradually acquiring an ivory-like patina.
Stones thicker than 10.1 mm are difficult to place on the board, while many Go players prefer stones that are 8.8 and 9.2 mm thick, considering these the optimum thickness for aesthetic and practical reasons.
Clamshell stones are cut as cylinders using a diamond coring drill, then professionally ground, sanded, shaped, and polished into the final product.
[citation needed] Yunzi is a style of stone first produced in the Tang dynasty in China by sintering a trade-secret mixture of mineral compounds including agate (resulting in the slightly yellow-green hue of traditional yunzi stones).
The firm claims their stones have the advantage of a pleasant sound when placed on the board.
The black pieces are dark, and when held to the light a translucent green hue.
During the opponent's turn, it is considered rude for players to rattle stones in the bowl.
The "correct" procedure is to decide upon one's move, then remove one stone from the bowl and place it on the board.
The keys to a loud click are the force of the middle finger and the late release of the stone.
[4] Although it is permissible to place one's stone at times with a loud, satisfying "thwack", one who does so with every move would be considered crude or vulgar.
For instance, when submitting to an opponent's threat, a quiet placement is more in keeping with circumstances; probing moves or clever responses may be slid slyly into place.
The ability to express oneself in the manner of making a move explains why one of the names for the game is "hand talk" ("shudan" in Japanese, "shoutan" in Chinese).
Standard care of stones (of any variety except slate and clamshell) generally involves washing stones in soapy water to remove oils and chalk by-products from their manufacture or storage protection.
A player traditionally places the lid upside down next to the open bowl and keeps stones there that they have captured from the opponent.
