A wide-range genjutsu (広範囲幻術, kōhan'i genjutsu, literally meaning: wide-range illusion technique), whereby Gengetsu, in conjunction with his summon, is able to manifest realistic mirages by reflecting the light using the water vapour, which is being spouted by the clam. As it is impossible for observers to distinguish from the real thing through normal methods, this property makes the technique ideal for concealing the actual location of either individual, resulting in confusion amongst the opposition as their attacks are rendered ineffective and they attempt to ascertain the pair's true positions. However, in order to maintain the illusions, the clam must continually exude the mist from its siphons, throughout the duration of the technique.
According to Gengetsu, the only method to end the technique is to defeat the real clam, but as the creature itself remains camouflaged within the mirage, this is no easy task, even if the summoner is providing beneficial advice. While the technique is in effect, both Gengetsu and the clam cannot be sensed through traditional means, with the exception of contact type methods.
- Fourth Databook, page 294
- Naruto chapter 552, page 12
- Naruto chapter 557, page 4