ヒカルの碁 16

"Since Sai's disappearance, Hikaru has given up go! Meanwhile, undefeated by his failure to pass the pro test, Isumi plays his heart out in China. His foreign training teaches him unique ways to handle the stress of mental challenges and competition. Upon his return, he asks Hikaru for a rematch! But how good will Hikaru's game be after such a long break--and without Sai?" -- from publisher's web site.