We have venerable Master Stones. This is the most important “base point” or the “foundation” of all our Go stone making processes.
Newly-hired craftsmen and screeners of Kuroki Goishiten have to learn what our Master Stones are and how to check every stone against them for comparison. Even long-experienced craftsmen and screeners are never allowed to skip this process.
If the stones do not comply with our Master Stone because of their unstable shape or any kind of uncomfortable feeling, they should be immediately rejected. During the entire process, we carefully check every stone in terms of their beautiful roundness, evenness between top and back faces, texture as well as right amount of thickness to prevent chipping and flaws. We always seek to produce Go stones of the highest quality so that our products will satisfy our customers’ senses of vision, hearing and touch.
Various Types of Rejected Go Stones
We inspect carefully every Go stone to screen out various types of rejection as shown below.
Mimi (rim) is too thin.
If the rim is less than 1mm thick or if there is no rim, a stone may easily chip.
Abacus Bead-shaped Go stones
Abacus bead-shaped stones are unstable and easily cause scratches on boards.
Dent between rim and sides
Skin scurf may attach and accumulate in a dent between the stone rim and sides The stone looks bad and is uncomfortable to play with.
Mimi (rim) is too thick.
If the rim is more than 1mm thick, the stone looks bad and players feel uncomfortable as a thick rim does not fit their finger tips.
Go stones that are too round
If a stone is too round, it looks bad and will not create any tremor when it is placed on a board.
Rim is sticking out (Kaeri)
If the rim sticks out too much, the stone may easily chip and is uncomfortable to play with.
Unparalleled rim (Kata-mimi)
If the whole rim is not totally parallel and presents a difference in thickness, the stone looks bad and will easily chip.
The top and back sides are not evenly shaped (Kata-yama)
If the top and back sides of a stone are shaped unevenly or do not have a uniform shape, the stone looks bad, is unstable and is uncomfortable to play with.
The top side is too flat
If either side is too flat, it looks bad. The stone is also uncomfortable to play with, skin scurf may easily attach and remain on the flat top, and the stone produces no tremor when placed on a board.
A groove between rim and sides
Skin scurf may attach and accumulate into a groove found between the rim and sides. The groove may easily chip.