Yellow Mountain Imports Yunzi Double Convex Go Stones (9.2 Millimeters, Size 33) with Bamboo Bowls Quality of Yunzi stones; this set of professional Yunzi go stones is China's finest; Yunzi stones have a balance and a deeply rich color that are instantly noticeable; the stones will actually look nicer over time as they absorb moisture and natural oils from your fingertips; they also leave an audible ''snap'' as you place them on the board. 181 black and 180 white genuine Yunzi stones included Yunzi stones details; the texture, symmetry, and precision of these stones are superior; each stone is a 9.2 millimeters (size 33) double convex stone measuring 0.36 x 0.85 inches (9.2 x 21.5 millimeters); Yunzi stones have been made for almost a thousand years in the same area of Yunnan province in southern China; the secret recipe for making Yunzi stones is closely guarded; rumor has it, however, that the ingredients consists of agate and Yunnan mountain stone Bamboo wood bowls; a set of two bamboo bowls (gosu) is included; each bowl is 6.3 x 4.3 inches (16 x 11 centimeters); these bowls fit stones up to 10.4 millimeters (size 37); securing bowl straps with hook and loop fasteners accompany the bowls to keep the lids secure during storage and transport Carrying case; the handy vinyl carrying case will protect the stones and bowls as you easily transport them from place to place 30 day return policy; here, at Yellow Mountain Imports, we want you to be satisfied with your purchase; you are backed by our 30 day no questions asked money back guarantee so you can buy with confidence