The Tatsumaki Zankukyaku (竜巻斬空脚 Tatsumaki Zankuukyaku?, "Tornado Slashing Air Leg"), also known as the Hurricane Scythe Kick, is a version of the Tatsumaki in the Street Fighter series. It is utilized by Akuma and Oni.
Like quite a few of Akuma's attacks, it has the properties of Ryu and Ken's Tatsumaki Senpukyaku. It hits multiple times like Ken's version, but is as strong as Ryu's version and faster, albeit harder to control. The EX Special version has Akuma spin in place, also similar to Ryu's.
In some games, particularly the Marvel vs. Capcom series, the attack takes on lightning-elemental properties. In Marvel vs. Capcom 3, an airborne Tatsumaki Zankukyaku doesn't knock down the opponent; in Ultimate Marvel vs. Capcom 3, the ground version also loses this property, but can still hit opponents into the air.
In Street Fighter V, Akuma's light and medium versions will travel horizontally as before but the hard version will rise up at an angle before Akuma kicks his opponent back down for the final hit. The EX version is the same (where Akuma performs a stationary Tatsumaki Zankukyaku).
The midair Tatsumaki Zankukyaku is one of Akuma's main cross-up tools. A common tactic is to followup a light Tatsumaki Zankukyaku juggle with a heavy Goshoryuken, especially in the corner; later games give this combo tighter timing.