A lock is a technique in Super Smash Bros. Brawl, Super Smash Bros. 4, and Super Smash Bros. Ultimate where a character can use low knockback attacks to combo an opponent on the floor that is "prone"; aka "lying down". An animation of the victim briefly bouncing off the ground signifies a lock. Some moves that lock are fast enough to be repeated, while others cannot be repeated fast enough to keep the opponent in the locked position, or have knockback scaling that causes the opponent to be launched at higher percents. Some moves will move a character across the stage farther than others, causing less damage buildup overall.
The reset was first introduced in Super Smash Bros. Melee, and was then incorporated into the locking mechanic as the only wake-up option that can be used afterwards, allowing for a punish as the opponent stands up. The character will stand up in an identical animation of a standard neutral get-up, with intangibility frames at the beginning.
Trying to perform a lock in Melee merely results in a reset, which the opponent can avoid altogether with ASDI. In Brawl, a reset can occur only after locking has ceased, which can result in zero-to-death combos. In Smash 4, it functions in the same way, but locking can now only be performed a maximum of three times before an automatic reset occurs (except in rare circumstances, see below). In Ultimate, this has been reduced to two times before an automatic reset; additionally, the reset no longer forces the opponent to use a neutral get-up (effectively resulting in a tech-chase). This can be considered a blend of the former locking and reset mechanics, respectively.
Percentages, weight, and angles are the most noteworthy properties in determining if a move will successfully lock or reset. Some moves only do so in very specific circumstances, while others almost always do. The listings below do not take any of these parameters into account, and only extremely character-specific or unwieldy locks are not to be listed. In every Smash game, including Smash 64, an instant getup with a grounded flinch will occur in any low-knockback situation a lock or reset cannot.
How to perform
Starting a lock or reset is often the most difficult part, as many skilled players will tech or DI away before hitting the ground, and will also get up as soon as possible to avoid it. Surprise or fast attacks causing a character to fall quickly on the ground can work, as well as taking advantage of various situations in which a tech cannot be performed. For example, in Brawl and SSB4, footstooling an airborne opponent will prevent them from being able to tech in any way while in tumble, though the upward momentum can cause the footstooler to be unable to follow up with a lock depending on their character. Learning to perform a shorthop footstool aides in this. For some characters, it is possible to fast fall an aerial with lock properties to cause a single bounce, then follow up with a jab lock or reset.
Types of locks
The most common type of lock is the jab lock, which can be performed by multiple characters. As the name states, it is done by hitting a fallen character with a jab, stepping forward, and hitting them again. The locked player can be moved to the end of the stage in Brawl, where the active player generally hits them with a charged smash attack as they stand up. Generally, it is done with only the first hit of the jab, but some characters can do it with the second hit as well. If one attacks too soon after each bounce, or use a move without lock properties, the character will snap to a standing position. Some jabs will only lock with certain hitboxes. An example of this is with Mario, where he cannot jab lock with the first hit of his jab if he hits them with the front of his fist, so he must be close to his opponent when he jab locks them. In SSB4, the jab lock only works up to three times. In Ultimate, a jab lock only works up to two times, although a change from previous games is that almost every character in the game is capable of jab locking except for characters with unique jabs such as Ganondorf and Roy.
Aerial move locks
A commonly used lock is Falco's laser lock, which, unlike other locks, has enough range to hit and lock characters on level ground with Falco regardless of distance (assuming tournament legal maps). Larger stages like Bridge of Eldin can cause a character to move far enough away that Falco's lasers cannot reach them. There are many followup options that Falco can use, such as his BDACUS. The easiest and most effective way to set up a Laser Lock is to land a down throw or grounded down aerial and immediately buffer the first hit of Falco's jab. Falco cannot always follow up with a KO move because of distance, reducing the effectiveness of the laser lock to damage building only. It should also be noted that the laser lock only works at percentages equal to or exceeding 80% as Falco's moves will not cause a tumbling animation until said percentage.
Not all characters can be laser locked, due to the height of their character model while lying down. For other characters, it is dependent on which way they fall, since the height of the hitbox can change if they fall on their face or on their back.
Kirby using Falco's lasers will shoot them lower, allowing him to lock more characters than Falco can.
In Ultimate, Falco's lasers do not travel as far as they do in Brawl, and he can only lock opponents twice with them before they reset due to the altered locking mechanics.
Most moves with a burial effect are able to lock an opponent indefinitely past the three hit limit in Smash 4 (one notable example being Villager's down smash), giving the possibility of 0-death combos in team battles. It is important to note, however, that a lock cannot be started using a burying move, as the opponent will reset before the lock is able to be continued. Burial moves cannot lock opponents in Brawl.
Many throws have a hitbox that collaterally damages nearby opponents. With proper positioning and timing, some of these throws are able to lock other opponents.
Other grounded move locks
List of locking attacks
Jab Locks are still possible in SSB4. However, in most cases, the opponent can only be hit three times before being freed. Moves that bury opponents are exceptions to this rule as most of them can lock infinitely. Moves that "lock" must hit the opponent within 25 frames of hitting the ground.