GO - 8mm Bi-Convex Glass Go Stones(Wood Bowls not included) Improve your game of Go with those Jang Stone II 8mm bi convex glass stones. Featuring a diameter of 8mm and a classic bi convex design, these stones provide a superior gaming experience, with smooth and consistent movement across the board. With a sleek, professional look, this set of stones adds both style and strategy to your next game. GO Stones (361) 8mm x 21mm Bi Convex Jang Stone II Glass in Carboard Color Box. (Bowls