The Sankon Tessō (Kanji: 散魂鉄爪, Hiragana: さんこんてっそう, English: Soul-scattering Iron Claws, Dub: Iron Reaver Soul Stealer), is an attack in the manga and anime InuYasha.
Sankon Tessō is used by the fictional character InuYasha whereby he swipes his claws through the air and sends yellow yoki shockwaves toward his opponent or some other object targeted for destruction. This is InuYasha's primary mode of attack when he is not wielding his sword, Tessaiga. Direct contact with his claws is not necessary to cause severe damage to an opponent, as the shockwaves themselves are often what slash the opponent to pieces.
Upon InuYasha's revival by Kagome early in the anime series, the viewer first sees him use this move to devastating effect as he quickly shreds an attacking yōkai-centipede while shouting the name of the attack. InuYasha's half-brother, Sesshomaru, is known to use his claws in a similar, if less flamboyant, fashion (Dokkasō (Poison Flower Claws)).
During his yōkai transformation, it appears that the shock waves take on a red color, however it only appeared to happen once, and since basically everything takes on a red hue when he is transformed it may not have been the shockwaves but simply showing the path his claws were traveling in. Also, whenever a red slash has appeared for this attack, it never follows with the usual dissolving that the attack usually produces, so it is very likely that the attack is simply Inuyasha slashing with his claws and not the energy burst.