V-cancelling

V-cancelling, or velocity cancelling, is a technique that decreases the knockback velocity of moves in certain situations. It was documented by in September 2015.

How to perform
Either on the frame or slightly before hitboxes collide (1-2 frames), the defending player must fully press the L button or R button. In order to V-cancel, the character must be airborne but not floating, not in hitstun, not in an attack animation, and cannot have fully pressed the L or R button within the last 40 frames. If done correctly, the initial knockback velocity is reduced to 0.95× the original, resulting in a 5% decrease in knockback.

How it works
V-Canceling is not a glitch, but an intentionally coded gameplay mechanic. The method of activation is similar to teching, in that both require fully pressing a shoulder button and have a 40 frame lockout period. However, not only is V-Canceling much more difficult to perform than teching due to the myriad of prerequisites and relatively tight 3 frame input window, but the difference in knockback is so slight that it often goes unnoticed during a match if it happens. Still, the technique is completely doable, and is often done on accident, with common situations including getting hit before teching on the ground or air dodging.

Applications
While the difference in knockback is small, it can be useful in dire situations. V-cancelling can be used along with other techniques such as DI and Smash DI to reduce knockback distance. Despite not being as effective as the other two techniques, it can be critical for surviving attacks that would otherwise result in a KO. For example, 's up smash can usually KO at around 88% on Pokémon Stadium; however, with proper DI used in conjunction with V-cancelling, he can survive up to 102%.