Every combo you have ever landed in a fighting game traces back to a single unintended consequence inside Street Fighter II. Not a design decision, not a playtest experiment, not a deliberate feature. A side effect.

Akira Nishitani, the lead game designer of Street Fighter II, explained it in October 2013 in a Twitter thread that was translated and covered by EventHubs and Game Developer. His account is the clearest primary-source explanation the fighting game community has ever received for how the foundation of the genre came to exist.

The Problem Nishitani Was Actually Solving

In the original Street Fighter II, executing a special move required precise directional inputs followed by a button press, timed to the frame. For players who were learning the game, the biggest frustration was input timing: if your attack button came a fraction of a second too early or too late relative to the directional sequence, the special simply would not activate.

Nishitani's solution was input leniency: a small timing window was added so that if players pressed the attack button slightly too early, the move would still register correctly. The goal was to make special moves feel more responsive and accessible, lowering the skill floor without affecting the competitive ceiling.