Momentum canceling is a staple technique in Super Smash Bros. Brawl's metagame that reduces the momentum of a character in midair, and makes characters harder to KO. The technique essentially exploits the use of hitstun canceling to not only cancel hitstun but to also reduce the momentum they received from the knockback by executing aerials, specials, or air dodges to slow down the knocked back character. Since, in Brawl, attacks and air dodges can be performed while tumbling and reeling, it is possible to use these moves, in combination with others, to slow a character's aerial movement, and avoid crossing blast lines and being KOd. A prominent example of a momentum canceling move is Mr. Game & Watch's Oil Panic, which negates all aerial momentum immediately, and may be used after tumbling has ended.
When combined with directional influence (DI), momentum canceling can allow characters to survive to damage percentages far higher than the percentage a character would normally (without momentum canceling or DI) be KO'd at. While less effective against attacks with high knockback scaling, such as Luigi's forward smash, this technique is essential in competitive play and helpful in casual matches.
In Super Smash Bros. 4, momentum canceling is technically still existent, but due to the changes to hitstun canceling (with players having to wait much longer to air dodge or use an aerial after getting hit), momentum canceling is functionally impossible to utilize, and characters in Brawl that were able to slow/halt their momentum can no longer do so in Smash 4. A prime example is Mr. Game & Watch, whose Oil Panic can no longer completely cancel momentum at all due to it being deliberately removed.
Momentum cancelling is possible due to a critical property of knockback; that is, that it still enables other sources of aerial velocity (such as falling) to build up normally, simply stacking with the velocity of the knockback, with the exception of moves such as Oil Panic which cancel it entirely. Ordinarily hitstun would prevent taking advantage of this, and hence fall speed is the only critical factor in determining overall distance once the magnitude of knockback has been calculated. However, Brawl enables the cancelling of hitstun by use of airdodging and use of aerials, and once the lag from the aerial or airdodge has ended, any special move which applies a velocity to the fighter can be used to alter the overall speed of the fighter. It is also possible to immediately initiate a fastfall if the hitstun is cancelled with an aerial, and assuming the player has not used up their jumps, midair jumping is also possible. Since lateral movement in the air is still disabled until such time that the hitstun would have ended automatically, the use of the initial horizontal velocity granted by jumping forwards or backwards is the only safe method of horizontal momentum canceling for characters who do not possess specials which apply a velocity to the character without causing helplessness.
How to perform
Momentum canceling involves two steps:
Vertical momentum canceling
To momentum cancel when launched vertically, a character must perform an aerial attack and fast fall. Both the aerial and the fast fall can be achieved by tapping down on the C-Stick (if it is set to Smash), since this will input a down aerial and fast fall simultaneously. It should be noted that stall-then-fall attacks do not assist vertical momentum canceling. Players whose characters possess stall-then-fall down aerials should instead tap the C-Stick in a different direction to carry out a different aerial, and tap the control stick down to fast fall.
Each character's potential to vertical momentum cancel hinges on the difference between the speed of their regular fall and the speed of their fast fall. Link, who possesses the largest difference, gains the most benefit from vertical momentum canceling, while Wolf, who has the smallest difference, benefits the least. It is important to note that, despite the existence of particular special moves that negate vertical momentum, all characters can survive longer by using this basic method, except Mr. Game & Watch. However, he only survives 3% longer using Oil Panic than the basic method (though the difference would be greater in a stage with a higher ceiling).
Character abilities chart
The following chart shows each character's vertical momentum canceling abilities, and ranks them in terms of their maximum vertical endurance, that is, the highest percentage at which they can survive vertical knockback. Characters were hit by Olimar's down aerial using Blue Pikmin, from the center of Final Destination. This information was compiled by Omega Tyrant.
Horizontal momentum canceling
Horizontal momentum canceling is notably more complicated than its vertical counterpart. The most basic method is to perform a character's fastest aerial, followed by a midair jump. If this technique is performed, every character is able to survive to percentages that are at least 1% higher than in cases in which it is not. The amount that each character benefits from this basic method hinges on two factors: the speed of their fastest aerial, and the initial lateral speed granted by their midair jump, in addition to air friction.
Horizontal air speed is not a helpful factor; for example, Wario has fast horizontal air speed, but is poor at momentum canceling horizontally. It should also be noted that Ike and Snake yield better results from using an air dodge instead of their fastest aerial. Coincidentally, these two gain the most benefit from the basic method. Unlike vertical momentum canceling, there are multiple special moves that aid horizontal momentum canceling; most influence the character's movement, and a few can cancel it completely.
Character abilities chart
The following chart shows and ranks each character's horizontal momentum canceling abilities. Each test was carried out by hitting the character from the centre of Final Destination with the tip of Wolf's forward smash. This information was compiled by Omega Tyrant.
* Indicates that the character does not make it back to the stage, and is KOd by the bottom blast line.
** Indicates that without DI, the character's special move provides no additional benefit.
If a character does not have a special move that negates momentum, their statistics in the "Special MC" columns are copies of those in the "Basic MC" columns, and are displayed in grey. Note that Lucario's forward aerial is most beneficial when used in basic momentum canceling with no DI, but his down aerial is most beneficial when used in momentum canceling with DI. As such, his down aerial appears in the position of other characters' "Special Moves". Similarly, Snake and Ike have air dodge ("AD") displayed instead of an aerial.
Momentum canceling special moves
The following are detailed descriptions of each special move that aids momentum canceling, in terms of characteristics, effectiveness, usefulness, and risk.
R.O.B.'s side special very mildly negates horizontal momentum, but does not move him far or put him into a helpless state. While only marginally beneficial, it does not pose any threats to R.O.B.'s recovery.
When combined with his up aerial, the fastest aerial in the game, Meta Knight's side special negates a substantial amount of horizontal momentum without DI, surpassed only by Donkey Kong's Spinning Kong. However, the use of DI provides very little extra benefit, allowing Meta Knight to survive at damages only 4% higher than instances in which DI is not used. The effectiveness of Drill Rush is further limited by the helpless state it leaves Meta Knight in, which can leave him vulnerable, especially when his slow horizontal air speed is taken into consideration.
Yoshi's side special negates a large amount of horizontal momentum, it is surpassed in this field only by Spinning Kong and Oil Panic, and it often allows Yoshi to survive potentially fatal blows if its first few frames are activated. Along with Oil Panic and Spinning Kong, it is the only special move that can negate vertical momentum as well as horizontal. However, its drawbacks hinder its effectiveness to the point of rendering it impractical under most circumstances.
While Egg Roll almost completely negates horizontal momentum, it does not give Yoshi any horizontal boost back toward the stage, it takes a long time to end the move, and renders him helpless upon its completion. Yoshi can never recover back to a neutral stage, even with his exceptional horizontal air speed. When momentum canceling vertically, Yoshi can survive longer by using the basic method and does not need Egg Roll. Overall, this move's usefulness for momentum canceling is very limited, since it is only practical to use on "walk-off" stages, or stages on which a blast line is very close to an edge.
Ganondorf's side special negates horizontal momentum a small amount. Without DI, Ganondorf cannot return to the edge of any neutral stage after being knocked horizontally. With DI, it is possible to return to the edge of some stages, but if he is knocked too close to a side blast line, on such a stage as Final Destination, this possibility diminishes. Flame Choke puts Ganondorf in a helpless state, thus, even if he is close enough to a stage to recover using the move, he will become an easy target for opponents due to his large size and slow air speed. All things considered, Flame Choke's usefulness for momentum canceling is minimal; it only negates a small amount of momentum, and Ganondorf can rarely make safe returns to stages after using it.
Like Diddy Kong's Monkey Flip, Zero Suit Samus' down special can negate horizontal momentum without putting her into a helpless state. It negates less momentum than Monkey Flip, and is only slightly beneficial in comparison to use of the basic method, but it is safe to use.
Diddy Kong's side special is relatively fast, negates horizontal momentum a decent amount, and does not render him helpless. As such, it can be considered one of the best horizontal momentum canceling moves in the game.
Mr. Game & Watch's down special is considered the best move in the game for momentum canceling: its use for this purpose even has its own special name, Bucket Braking. Oil Panic cancels all momentum on its first frame, both horizontal and vertical, thus, as long as Mr. G&W has enough time to use the move, his movement will halt and restrain him from crossing any nearby blast line. Oil Panic is also an extremely low risk move, as it does not move Mr. G&W in any direction or render him helpless. This allows him to make a safe recovery, and prevents opponents from attacking him while the move is executed. Mastery of this technique is essential for competitive G&W players. It should be noted that Oil Panic will not momentum cancel when the bucket is full.
Alongside Spin Charge and Quick Draw, Jigglypuff's side special is one of only three special moves that will aid a character with the use of DI, but provide no benefit without it. Pound negates horizontal momentum a very small amount, but it does not leave Jigglypuff helpless, thus, its use is safe.
Sonic's down special is another of three special moves that assist horizontal momentum canceling with the use of DI, but are of no benefit without it. Its momentum canceling effects are minimal, and it moves Sonic toward the stage, which can be hazardous. However, he will move quickly and Spin Charge will not induce helplessness, so the move is relatively safe.
Overall the second best momentum canceling move in the game, second only to Oil Panic, Donkey Kong's up special move, Spinning Kong, completely negates all momentum upon its first frame of activation, both horizontal and vertical momentum. This, in combination with his fast back aerial and his heavy weight, allows him to survive longer than every other character in the game when knocked horizontally, including Bowser. It puts him in a helpless state however, which is the reason Oil Panic is considered superior. Its landing lag may also leave DK vulnerable upon his return to the stage, but Spinning Kong can always cover the distance required to return to any neutral stage after momentum canceling. It also negates vertical momentum as well, but is impractical for this task other than getting hit diagonally upward as a result of DIing upwards as it leaves Donkey Kong helpless and Donkey Kong can survive longer vertically through the basic method.
The Ice Climbers' side special will negate horizontal momentum a small amount. When using the move together, the Ice Climbers are able to return to the stage, but a solo Climber cannot. Squall Hammer is moderately risky when used for momentum canceling, as it puts Ice Climbers into a helpless state upon its completion, which can be dangerous.
King Dedede's up special negates a decent amount of horizontal momentum, despite projecting him upwards. When using the move to momentum cancel, Dedede cannot return to neutral stages without DI. It is possible to do so with DI, but this may require the player to carefully time its cancel in order to grab a ledge without self destructing. The Super Dedede Jump moves Dedede quickly, and it can be difficult for an unprepared opponent to punish. However, its use it still risky, as performing it without the use of DI is often fatal, and using the move after being knocked offstage by too weak a hit can result in punishment.
Pikachu's side special negates horizontal momentum moderately, and does not leave him helpless. The move has a large amount of ending lag, so its use could leave Pikachu close the stage and vulnerable to reactive opponents if used after non-lethal knockback. However, Skull Bash is still considered one of the safer momentum canceling moves.
Pikachu's up special negates horizontal momentum exactly as well as Skull Bash, but is inferior for this task as it leaves Pikachu helpless. It is interesting to note that Pikachu is the only character with two special moves that benefit his horizontal momentum canceling ability more than the use of the basic method.
Ike's side special is another of three special moves that assist horizontal momentum canceling with the use of DI, but are of no benefit without it. Unlike the other two, it negates a large amount of horizontal momentum with DI, however, it also leaves Ike helpless and vulnerable, and its use without DI is fatal. For maximum benefit, Ike must successfully use an air dodge to end tumbling, which requires different timing and faster reflexes in comparison to the use of aerial attacks. While its momentum negation properties are strong, Quick Draw is very risky and difficult to perform correctly and safely.
The following video demonstrates the momentum canceling ability of Donkey Kong's Spinning Kong.
In Super Smash Bros. 4 and Super Smash Bros. Ultimate
Momentum canceling is still present in Smash 4 and Ultimate but due to the changes to hitstun canceling, it is almost impossible to utilise, severely limiting any character's endurance. Therefore, momentum canceling is not nearly as abusable as it was in Brawl. Because of this, aerial momentum canceling is no longer existent and only special moves can slow/cancel momentum. Also good DI would usually help survive for slightly longer combined with momentum canceling. Here are a list of characters and special moves that can cancel momentum:
Villager's side special can completely negate all momentum, both horizontally and vertically, upon its first frame of activation and is safe to use after being launched far. It is not necessary, and generally not recommended, to ride the rocket, as Balloon Trip is the safer means of recovery. It may be advantageous to aim toward the blast line when using the move for momentum canceling, so that the rocket will despawn and the move can be used again sooner.
Donkey Kong's Spinning Kong in terms of momentum canceling functions exactly the same as it did in Brawl. Donkey Kong's up special move, Spinning Kong, completely negates all momentum upon its first frame of activation, both horizontal and vertical momentum. This, in combination with good DI and his heavy weight, allows him to survive longer than every other character in the game when knocked horizontally and vertically, including Bowser. It puts him in a helpless state however, which might consider Villager's Lloid Rocket to be superior in terms of safety. Its landing lag may also leave DK vulnerable upon his return to the stage, but Spinning Kong can always cover the distance required to return to any neutral stage after momentum canceling. It also negates vertical momentum as well, but is impractical for this task other than getting hit diagonally upward as a result of DIing upwards as it leaves Donkey Kong helpless. However, due to the changes to hitstun canceling, Spinning Kong's very powerful momentum canceling is almost impossible to use effectively because of the lack of being able to use DK's fast back aerial to end hitstun early. Also, DK's customs Chopper Kong and Kong Cyclone are the same (Smash 4 only).
Yoshi's side special almost functions exactly the same as it did in Brawl'. Egg Roll completely negates horizontal momentum, it is surpassed in this field only by Spinning Kong and Lloid Rocket, and it often allows Yoshi to survive potentially fatal blows if its first few frames are activated. Along with Lloid Rocket and Spinning Kong, it is the only special move that can completely negate vertical momentum as well as horizontal. However, its drawbacks hinder its effectiveness to the point of rendering it impractical under most circumstances. While Egg Roll completely negates horizontal momentum, it does not give Yoshi any horizontal boost back toward the stage, but unlike in Brawl, Yoshi can end Egg Roll earlier and it no longer renders him helpless. Yoshi can now possibly recover back to a neutral stage in combination with his great horizontal air speed.
Wario Bike can reduce an extreme amount of horizontal momentum as long as it has already been activated (when the bike is moving forward). This might improve Wario's endurance a little bit but due to the changes to hitstun canceling, it is practically impossible to use as Wario can still drift and be KO'd during Wario Bike's startup. Wario Bike can also help survive vertical momentum despite the fact that it does not actually cancel vertical momentum at all. This is because Wario Bike makes Wario himself immune to the top blast lines.