Tatsu is short for Tatsumaki Senpuu Kyaku (TAHts-MAHk Sen-Poo KEE-ock); a move used in the Street Fighter series. Only practitioners of Shotokan Karate are able to use this move. It is executed by moving the joystick a quarter of a circle back, starting with the joystick in the down position and then press the kick button(s). Because Tatsumaki Senpuu Kyaku is a mouthful to say, people usually call it a hurricane kick, Tatsu, or QCB kick.
I did: crouching jab, jab, forward, link into short Tatsu, into fierce Shoryuken.