Hikaru no Go Hints & Cheats

According to Hikaru no Go author Hotta Yumi, there is a secret one-color igo mode at level 10, where both players use white (or black?) stones.

You must score 3700 points. Play Touya Kouya on a 19x19 board with a 4-stone handicap for Touya, and do not seek Sai's advice. This is the suggestion Konami made to Hotta Yumi. However, she exceeded 3800 on a 9x9 game with a 3-stone handicap.

Konami's response was ''Luck is also important.''