Edge-guarding or edgeguarding, also known as intercepting in Super Smash Bros. Melee, is the attempt to prevent an off-stage recovering opponent from reaching the stage, thus causing them to be KO'd. Players can achieve this in many ways, and the struggle between an edge-guarder and their recovering opponent often leads to many strategies and mindgames. The anti-strategy to this is the guard break.
There are two main methods of edge-guarding. One is to run or jump off the stage and attack; this is often done by characters with great jumping ability, which includes multiple jumps and good recoveries such as the Robo Burner. The other is to stay on the stage and attack the opponent when they recover should they fail to sweetspot the ledge. This is mostly done with down- smashes and tilts, and even some projectiles.
Any character can edge-guard, although some are better at it than others. A character's ability to edgeguard offstage is determined by two factors: the length and safety of their recovery, and the utility of their aerial attacks. The most prominent example is Meta Knight, as his recovery is effectively immune to edgeguarding, and because his aerials are quick and send opponents on favorable trajectories. However, some characters are strong edgeguarders despite having sub-par recoveries; Ganondorf is the best example. His recovery is slow and short, but all of his aerials are deadly offstage.
Certain characters are worse at defending themselves from edge-guards. These are generally characters with predictable recoveries (like Captain Falcon or Ike), slow recoveries (like Ness or Lucas), characters reliant on tether recoveries (like Olimar in Brawl or Ivysaur), or characters without a damaging recovery move (like Lucario in Brawl or Olimar in SSB4).
In general, the recoveries of the cast have improved across the games. In Smash 64, aside from Pikachu and, to a smaller extent, Mario, all characters have predictable recoveries, leaving them vulnerable to edgeguards, which is further compounded by the game's high hitstun.
Melee recoveries, while still rather predictable, are benefited by ledge-teching. Jigglypuff and Samus are well-known for their recovery ability, with the former having arguably the strongest edgeguarding ability in the game. Melee introduces meteor cancelling, which makes meteor smashes much less potent at securing offstage KO's. However, the increased falling speeds and gravity make semi-spikes more effective. Certain attacks, known as spikes, have downwards knockback that are not recognized as meteor smashes, and characters who posses these moves often utilize them in their edgeguarding, most notably Marth.
In Brawl, recoveries are overall longer, and the larger ledge sweetspots, as well as the auto-sweetspot mechanic, make edgeguarding less effective. The meteor smash recognition window has been expanded, removing the spikes of the previous game. Meta Knight is infamous for his immunity to being edgeguarded, due to the his plethora of recovery options, with his recovery being the best not only in Brawl, but arguably the entire series, and this grants him his powerful offstage game. Brawl's floatier physics, low hitstun, meteor cancelling and the aforementioned changes to ledge sweetspots arguably make edge-guarding in this game the least effective out of all four iterations. In these three games, edgehogging is a commonly used tactic to stop opponents who aim their recoveries to the ledge.
In Smash 4, recoveries on their own were generally buffed, and ledges were reworked to remove edgehogging, reducing the effectiveness of on-stage edge-guarding. However, meteor cancelling has been removed in Smash 4, making meteor smashes as deadly as they were in Smash 64, and planking is practically impossible. The new ledge-stealing mechanic can set-up recovering opponents for an attack, most commonly a back aerial. The longer recoveries enforce and encourage more aggressive offstage play, as offstage edge-guarding carries much less risk than before, since an edge-guarder can no longer be edge-hogged if their attempt is unsuccessful. Also, the improvements to recoveries are not consistent across the cast. Marth's recovery is largely unchanged from before; Fox's recovery is twice as long as in Brawl, as Fox Illusion and Fire Fox can now be used in tandem; and Ganondorf's recovery is even worse due to his lowered air speed and the removal of grab-armor, and Charizard suffers severely with the loss of gliding. Most notably, Smash 4 introduces Little Mac, whose recovery is undoubtedly the worst in the entire series.
Lastly, in Smash 4, teching cannot be performed during hitlag, causing certain stage-spikes to be un-techable, and the new ledge mechanics make stage-spikes more common than in past games. All these changes have contributed to more offstage battles in competitive play, as edge-guarding is much safer while still rewarding if successful. As in Brawl, Meta Knight is noteworthy for his edge-guarding ability, along with characters who possess useful meteor smashes, particularly Captain Falcon and Ganondorf.
The simplest and safest way to edge-guard is to stand at the edge and throw attacks - often a powerful forward smash, down smash or down tilt that can hit even an edge sweet spotting enemy. While this method of edge-guarding requires the least set-up, it is often thwarted by sweet-spotting or ledge-teching.
In a similar strategy to sitting on stage, a character with projectiles (especially projectiles affected by gravity, like Peach's turnips or Mario's fireballs) can stand by the edge and try to interrupt a faraway, recovering opponent. This strategy is very safe, in that players are very unlikely to be hit while edge-guarding in this fashion, and it can be combined with both edge-hogging and attacking from on-stage.
A risky, but deadly, way of edge-guarding is to jump off-stage and interrupt the opponent in mid-air. The recovering enemy has few options by which they can defend themself, such as using aerial attacks, air dodging or directing themself away from the edge-guarder. When using this style of edge-guarding, most characters put their own life in jeopardy, being so far off-stage. If, however, the edge-guarder is able to land a powerful aerial attack (like Captain Falcon's Knee Smash) far off-stage, their enemy will almost certainly get KOed. Even if unsuccessful, the edge-guarder can often edge-hog the recovering opponent anyways, pre-SSB4.
With most characters, it is best to avoid using the second jump before hitting the opponent. Many characters will not be able to make it back without it. Characters such as Jigglypuff, Kirby, and Meta Knight are very useful characters to use for this strategy. Their multiple jumps allow them to go far off stage and deliver an aerial attack.
A common way to edge-guard is to edge-hog, or grab the ledge so that the opponent cannot. There are several ways to reach the ledge when standing on-stage. The two most common ways are to face away from the ledge and either short hop or wavedash backwards. Many players, when wavedashing backwards, make the mistake of standing too close to the edge before wavedashing, thereby air dodging off-stage and self-destructing. Note also that with some characters, it is possible to fast-fall the wavedash off the stage and in effect grab the edge sooner.
Usually, an edge-hogger rolls the moment the recovering enemy uses their third jump, gaining invincibility frames and defending themself against damaging up special moves. Edge-hogging is effective against sweet-spotting, but can be beaten by an enemy that comes fully on-stage in their recovery.
When an enemy lands fully on-stage they are often caught in the lag of their third jump. Edge hopping is often the method to keep them off the stage. This causes one to return to the starting position of choosing which edge guarding technique to use, but the opponent has slightly more damage, leading to a constant edgeguard game.
Only possible in Super Smash Bros. 4, grabbing onto a ledge that has already been grabbed by another player will gently remove them from the ledge. While ledge trumping was intended to negate edge-hogging, it can still be used as an effective edge-guard; an on-stage player ledge trumps a recovering player by running off-stage and fast-falling onto the ledge as soon as the recovering player grabs it. This causes the recovering player to automatically let go of the ledge and they cannot take any action for a moment, allowing for an easy combo, such as Sheik's back air. In addition, the removal of ledge re-grab invincibility can be exploited by a ledge trump edge-guard.
A somewhat underutilized ability, deterrence, is basically fake off-stage guarding. The player would make to jump towards the opponent trying to recover, but instead return to the stage without ever engaging the enemy. If done convincingly, the opponent will attempt to evade the non-existent attack and hopefully miss the ledge or dodge right into a different attack.
While this strategy works against newer players, it usually requires a twist against more advanced combatants. In this case, doubles play is usually necessary.