Name: Silent Homicide Technique (無声殺人術, Sairento Kiringu; English TV "Silent Killing Technique")
Type: General skill
Users: Zabuza Momochi, Kakashi Hatake, Mizuki
Debut (Anime):Naruto Episode 7
Debut (Manga): Chapter 12
As the name suggests, this technique is simply a very quiet method of killing an opponent, usually from behind with a blade. Additionally, because the user is very silent, it cannot be defended against. The user will often slit their opponent's throat, preventing any cry that might give them away. Zabuza was a master of this technique, and was even good enough to track and kill opponents through sound alone.
The Hidden Mist Technique was used by Zabuza in conjunction with this technique.