Go-Steine, Jitsujo. 7,5 mm x 22 mm
The black stones aer made from Nachiguro slate mined in Wakayama prefecture, other than thickness there is no difference in quality. The white stones are made from a shell harvested near Lower California, Mexico. The thickness and grain pattern determines the the price of a set.
Jitsujo shell and slate stones grain is irregular and less clear.