The Four Witches Technique (四妖拳 Shiyōken, literally Four Supernatural Fists) is a technique in which its user temporarily grows two extra arms from the back, seemingly under the shoulder blades. This allows the user to attack with twice the intensity that he or she would normally be capable of.
Tien is the only known user of this attack, perhaps because of his being a superhuman.  If this is the case, it is possible that Chiaotzu is capable of the technique as well, though he never demonstrated this ability. Tien only used the Four Witches Technique during his fight with Goku during the 22nd World Martial Arts Tournament, where it proved ineffective when Goku was able to dodge and counter the attack with ease. Afterward, Tien moved on to stronger attacks.