On a chilly Sunday afternoon in January in downtown Osaka, a group of young Japanese women in kimono were drinking green tea and eating chocolate cake while excitedly chattering away. The topic was their respective rankings in the ancient Asian mind sport of go.

Later, when the talk died down, six of them formed three pairs who sat facing one another at small tables lined up in rows. And then - silence. The only sounds were soft classical music playing in the background, punctuated by the clinking of polished black and white stones when one of the women dipped her hand into a bowl to pick one up and place it on the board with a gentle tap.