A Chinese pro player. Outwardly an amicable man with a relaxing attitude, Yang Hai is in fact very mature-minded and extremely keen on Go psychology. He's also known for his language hobby (he can speak Korean, Japanese and English fluently) and his immergence in computer Go programming.

Spoiler

Yang Hai befriended Isumi when the latter traveled to China during an exchange tournament, and helped Isumi overcome his greatest opponents (his lack of self-confidence and emotional instability) to defeat many Chinese pro players he was initially intimidated by. He later became the manager for China team in the Hokuto cup, and witnessed the ensuing chaos between Hikaru and Ko Yeong-ha over Yeong-ha's provocative statements against Shusaku. After the matches between the Korea and Japan team, he engaged in a discussion with Touya Kouyo regarding Sai's mystery, and unbeknownst to himself, got extremely close to solving Sai's identity (a ghost of Shusaku who exists in modern times).