Purposefully leaving a microscopic gap in Ryu's offensive string in Street Fighter exploits the opponent's anticipation by tricking them into pressing a counterattack button…

The trap is in the timing

In Street Fighter, a frame trap is a deliberate pause in an attack sequence that tempts a blocking opponent to retaliate. The attacker’s next strike is timed to catch that response before it becomes an attack of its own.

The key is the difference between recovery and startup. After a move is blocked, the attacker may recover first and be able to act while the defender is still stuck in the block animation. If the attacker follows immediately, the defender may have no chance to act. But waiting a few frames can create a narrow opening: the defender sees a possible turn to attack and presses a button, yet the incoming strike arrives while that button is still starting up.

Why a small gap can work

A move’s startup is the time between pressing the attack button and the hitbox—the part of the move that can connect—becoming active. During startup, the character can often be hit. A frame trap exploits that vulnerability: the defender’s counterattack has begun, but its hit has not yet reached the attacker when the follow-up lands.

The timing has to be chosen carefully. Leave too little space and the defender may remain unable to respond; leave too much and their attack can become active first. The useful gap depends on the moves involved, including their startup speeds and the advantage created by the first blocked attack. In a game running at 60 frames per second, even a handful of frames is only a fraction of a second.

A read, not a guaranteed hit

A frame trap works because the defender must decide whether the apparent opening is real. If they keep blocking, the follow-up may simply be blocked too. If they try a quick attack, they risk being struck during startup. The attacker is not forcing a mistake so much as presenting a tempting choice and preparing for the most likely response.

That makes the tactic useful beyond its immediate damage: repeated traps can make an opponent hesitate, giving the attacker more room to continue applying pressure. The tiny pause matters because it turns the defender’s expectation—“it’s my turn”—into the opening the attacker was waiting for.