Suijutsu

Suijutsu (水術, Water Skills) is a jutsu type exclusive to the Umigakure village. Since nearly the entire village was slaughtered the only living user of the special jutsu type is Otohime Watatsumi. Suijutsu is a subspecies of Taijutsu that focuses on combat in water or combative swimming. Suijutsu has many differences from Taijutsu. For one it isn't as linear, but instead users are taught how to fight from all angles which is possible since they are in the water. The possible movement techniques that come from this are called Water Combat Maneuvering as they have a lot of similarties to Air Combat maneuvering. In fact, Suijutsu is very much like dogfighting in general. They can even use projectiles while sticking to martial arts by firing pulses through the water with their strikes. According to Otohime masters of Suijutsu like her can swim at super sonic speeds and maneuver around with the utmost skill, which makes them a huge threat in the water.

Trivia

 * Suijutsu was inspired by its real life counterpart and the idea was solidified by Fishman Karate from One Piece and dogfighting.