According to Kawamatsu, fighting against the Kappa-ryu is like trying to swim against raging waters which makes full use of his fish-man strength to inflict powerful blows. When wielding his Soto Muso, Kawamatsu was able to blow away several men charging against him, taking them down with a single blow.
Menamu-gawa (滅南無川,Menamu-gawa?, literally meaning "Destructive Hailing River): Kawamatsu lunges toward his opponents and quickly cuts them down. In the anime, he spins rapidly while charging towards his opponents, creating a small but potent horizontal whirlwind around himself while cutting them. It was first used against several Beasts Pirates guards in the Prisoner Mine.Namu (南無,Namu?) is a transliteration of Sanskrit नमस् (námas, literally "to bow") and it is used in Buddhist salutations or expressions of faith. In the VIZ manga, this is called River of Retribution.
Yorikiri (寄り斬り,Yorikiri?, literally meaning "Frontal Force Out Cutter"): Kawamatsu performs a slash and sends opponents flying away through sheer force. It was first used against several Beasts Pirates guards in the Prisoner Mine.
Amano-gawa (海野川,Amano-gawa?): Kawamatsu jumps above his opponent, holding the blade behind him, then releases a powerful frontward flying slash attack that expands in a circular pattern. It was first used against Kaido. This is called River of Sea in the Viz Manga.
Kawamatsu named this swordsmanship style after the mythological Kappa.