Shieldstun

Zero Suit Samus currently in shieldstun from Snake's jab.

Shieldstun is an inactionable period that occurs when a character's shield is hit. It is comparable to hitstun, in that it occurs after hitlag and only for the defending character. While the attacker still experiences the hitlag of the move, they do not undergo shieldstun, allowing them to move again before their opponent can if the ending lag of the attack is low. During the period of shieldstun, the shielding player cannot perform any of their normal out of shield options, rendering them stuck. Several fast multi-hitting moves (such as Fox's or Yoshi's down aerials) hit fast enough to keep an opponent in shieldstun for the duration of the move, as each hit lands while the opponent is still in shieldstun from the previous hit; this is usually referred to as a "blockstring", a term stemming from similar situations with block mechanics in traditional fighting games. In addition to not being able to perform out of shield options, players in shield stun cannot release the shield, adjust the tilt of their shield, shield drop, or change their shield's density. Attempting to perform any of these actions while in shieldstun will have them happen the frame shieldstun ends instead.

With the inability to jump, grab, roll, or spot dodge out of their shield, the player in shieldstun is very susceptible to another hit or a grab. Though it is rare, this can sometimes be used to the point of breaking a player's shield, as with Fox's and Falco's pillaring combos. A combo meant to lock an opponent in shield until their shield breaks is known as a shield break combo. However, outside of SSB, these combos are not perfect, as all other combos on shield have gaps in shieldstun. Thus, the goal of shield combos in Melee is rarely to outright break shields: it is far more likely an attempt at causing a shield poke, or to bait and punish a roll, grab, or spot dodge. Still, since gaps in shieldstun must exist it is necessary to mixup where and for how long these gaps fall. Doing so covers different out of shield options that the defending player might want to use. As an example, a double shine covers the grab-sized gap that is normally left after a waveshine or a jump out of shine into an aerial, and grants the attacker the hit they were looking for.

In Super Smash Bros.

In Smash 64, shieldstun is extremely high. When hit on shield, the majority of moves leave the defending player in such a long period of shieldstun, that another hit is nearly always guaranteed. This is especially apparent with aerials with the use of Z-cancelling. This, along with the lack of perfect shielding, makes shield break combos easier and far more frequent. Some moves, such as Kirby's up tilt, are notorious for breaking shields on their own with repeated use.

The formula for shieldstun frames in Smash 64 is d * 1.75 + 3 in the Japanese version, and d * 1.62 + 4 in the international versions, with both results rounded down, where d is the amount of damage the attack would deal if not shielded (therefore, shield damage is not accounted for). Compared to the international versions, the Japanese version has even more shieldstun for attacks dealing more than 10% damage, but the same or slightly less for attacks dealing less than that amount.

In Super Smash Bros. Melee

In Melee, shieldstun duration in general was reduced. A large difference from other Smash games is the introduction of analog shielding. The analog shield level used when blocking affects shieldstun: the lighter the shield, the more shieldstun the blocker suffers. The formula for shieldstun frames in Melee is 200 / 201 * (((d * (a + 0.3)) * 1.5) + 2) rounded down, where the values correspond to the following:

• d is the amount of damage the attack would deal if not shielded, rounded down.
• a is 0.65 * (1 - ((s - 0.3) / 0.7)), where s describes the analog shield level used. A fully depressed trigger corresponds to s = 1.0, while the lightest possible analog press that still yields shield corresponds to s = 0.30714.
  • The general formula can be approximately simplified to d * 0.45 + 2 for a full press, and d * 1.925 + 2 for the lightest press, resulting in a significant difference. For example, an attack that deals 13% damage will inflict 7 frames of shieldstun with a full shield, and 27 frames with the lightest possible shield.

This amount of shieldstun, while heavily reduced, is still sufficient to leave smart and quick attackers at an advantage. Many moves are unsafe on shield, and it is possible for defending players to capitalize on such hits. But many moves, especially certain aerials, are still safe. Pressuring an opponent's shield is challenging and risky, but highly rewarding. Often, despite a move merely breaking even on shield, or even being a few frames negative, the attacker will still have an advantage. Options out of shield, especially movement, are so limited that good spacing or quick dash dancing out of lag allow the attacker to safely pressure despite frame disadvantage.

While Melee generally has no input buffering, it is possible to buffer out of shield options by holding the C-stick during shieldstun. The character will then jump, roll, or spot dodge on the first frame after they leave shieldstun, depending on the direction held.

Yoshi is a notable exception to these rules. While he cannot jump out of shield in this iteration, he suffers no shieldstun whatsoever, which combined with the other unique properties of his shield, gives his shield game a very different dynamic to the rest of the cast.

In Super Smash Bros. Brawl

In Brawl, shieldstun was further reduced. In terms of frame advantage, very few attacks are safe on shield. Combined with the lowered time to drop shield (taking 7 frames instead of 15), this means that hitting shields in Brawl puts attackers in a much more vulnerable position. This leads to a drastically more defensive metagame, where spacing attacks properly on shield is far more crucial, or a punish is nearly guaranteed otherwise. Additionally, Yoshi's shield is no longer immune to shieldstun, and his shield drop takes a much higher 17 frames compared to the rest of the cast; in combination with him still being unable to jump out of shield, this gives him a significantly worse shield game.

The approximate formula for shieldstun frames in Brawl is d * 0.375, rounded down. As a result, attacks that deal less than 2.7% damage inflict no shieldstun at all.

In Super Smash Bros. 4

In Smash 4, shieldstun was originally thought to have been reduced again from Brawl, but further testing showed this to be false. The formula for shieldstun frames prior to version 1.1.1 was originally d * 0.39 rounded down, which resulted in almost negligibly higher shieldstun than in Brawl; only a few key damage values generated one extra frame of shieldstun, even up to notoriously high percents (above 30%), and moves that dealt less than 2.6% damage still inflicted none at all. In combination with the cast's generally higher landing lag, ending lag, and/or lower damage values, especially for top and high tier characters, as well as shield pushback being decreased (with the effect of edge slipping on it being particularly weakened), this originally made Smash 4 an even more defensive game than Brawl, with heavy reliance on out of shield retaliation instead of direct pressure. Yoshi was also given the ability to jump out of shield and the standard 7 frames of shield drop lag, no longer differentiating his shield game heavily from the rest of the cast.

However, following version 1.1.1, shieldstun from direct attacks was increased dramatically, to the point of being higher than in Melee, and received further specialization for various cases. The new formula is d * 0.58 * i * p + 2 rounded down, with the values corresponding to the following:

• d, like in the previous formulas, is the damage the attack would deal if not shielded.
• i is 0.5 for indirect attacks (such as projectiles), and 1 otherwise, resulting in a general multiplier of 0.29.
• p is 0.66 if the attack is perfect shielded, and 1 otherwise, resulting in general multipliers of 0.3828 and 0.1914 for direct and indirect attacks, respectively.

As a result of this formula, all attacks once again inflict shieldstun regardless of their damage output, and direct attacks are especially safer, to the point of various landing aerial attacks only being a few frames negative on shield with proper timing. In turn, perfect shielding having an effect on shieldstun ties further into its purpose of being much more precise, yet much more rewarding than normal shielding. Compared to previous versions of Smash 4, these changes allowed several characters to play more offensively, though due to out of shield options still being relatively fast and highly rewarding, as well as the aforementioned damage/lag nerfs, the game remained generally more defensive than Melee. On the other hand, the specific multiplier for projectiles made them generally safer as well, but to a lesser extent and only up to high damage values, preventing powerful ones such as Charge Shot from becoming too difficult to punish.

Version 1.1.3 of the game added an additional wrinkle to shieldstun: if a character is trapped in shieldstun for at least 10 hits (or in more colloquial terms, a blockstring), they are allowed to cancel it with a roll or spot dodge, and the intangibility of either option comes out immediately on frame 1, regardless of their coded startup. Practically, very few moves can hit a shield enough times for this to trigger; the looping hit of a charging Aura Sphere is the most noticeable. In the case of said move, this mechanic allows shielding characters to escape it if they are trapped by it at the ledge, where they would otherwise be forced to shield SDI or have their shield broken.

In Super Smash Bros. Ultimate

Shieldstun has been adjusted further in Ultimate, with more specific cases introduced than in Smash 4. The new formula is d * 0.8 * t * m + 2, rounded down, with the values corresponding to the following:

• d, like in the previous formulas, is the damage the attack would deal if not shielded.
• t is 0.8 for smash attacks, 0.33 for aerial attacks, and 0.29 for indirect attacks (such as projectiles); due to this, the former results in the same general multiplier of 0.58 as in Smash 4, while the other two result in general multipliers of 0.264 and 0.232, respectively. For indirect smash or aerial attacks (such as Mega Man's forward smash and down aerial), only the indirect multiplier is used. In other cases, the value is 1.
• m is a shieldstun multiplier, a move property new to Ultimate that can be specified for each hitbox. This is mostly employed by rapid jabs and dash attacks, which use a higher multiplier than usual to either prevent shielding opponents in range from escaping them or to decrease their punishability (respectively). However, a few other moves possess them as well, such as Ridley's Skewer, which uses a much lower multiplier than usual (0.2×) to prevent its skewering hitbox from otherwise producing ludicrously high shieldstun, as it deals 45% damage (likewise, it has a high amount of negative shield damage to prevent it from instantly breaking a shield). Shieldstun multipliers also affect the amount of pushback inflicted on the shielding fighter, further affecting how punishable attacks are out of shield.
• Perfect shielding no longer directly affects the shieldstun duration. Instead, perfect shielding characters enter a unique state that allows them to act 3 frames earlier compared to the shieldstun they would receive if used against a direct attack, and 1 frame earlier if used against an indirect attack, barring specific cases.

As a result, shieldstun remains unchanged for smash attacks compared to Smash 4, but is increased for direct special moves and all other ground attacks; tilt attacks in particular are noticeably safer on shield. Conversely, it is decreased for aerial attacks and projectiles, most significantly the former. Further adjustments in Ultimate include short hopped aerial attacks having a 0.85× damage multiplier, further reducing the shieldstun of some of them (albeit slightly), and stale-move negation applying on shield, weakening repeated pressure with a particular attack. However, due to the universally lower landing lag, the general safety of aerial attacks on shield remains unchanged, with some of them being slightly safer. Furthermore, shield dropping takes longer (11 frames instead of 7), while shield grabbing after shieldstun has increased startup by 4 frames. Overall, attacking shields in Ultimate is more favorable, with options to safely punish out of shield being riskier (albeit still highly rewarding), promoting more offensive play.

The ability introduced in version 1.1.3 of Smash 4 to dodge-cancel blockstrings of at least 10 hits returns as well, and is now applicable to several other moves, most remarkably every rapid jab, due to their increased shieldstun and much faster hit rate. This renders it vastly more useful for punishing such moves, as in the case of rapid jabs, the shielding character can usually roll behind the attacker, who will then be forced to unleash their rapid jab's finisher and become much more vulnerable. This mechanic's larger notoriety has led to it being referred to as shieldstun canceling by the community.

List of moves with shieldstun multipliers

Due to a glitch, while some moves such as Areadbhar and Skewer have a shieldstun multiplier coded only for specific hitboxes (in both cases, the sweetspots), the game applies the multiplier to all hitboxes of the move during frames where the specified hitbox is present. As a result, Areadbhar's grounded version inflicts regular shieldstun during its first hit frame (where the sweetspot isn't present), but applies the multiplier to all hitboxes in the next frames, while the aerial version applies it to all hitboxes fully throughout.

Character	Attack	Multiplier
Banjo & Kazooie	Rapid jab	6
	Wonderwing	0.48 (clean) 0.28 (late)
Bayonetta	Rapid jab	15
Bowser Jr.	Rapid jab	8
	Down tilt (hits 1-2)	1.2
Byleth	Rapid jab	9
	Failnaught (uncharged)	1.1
	Areadbhar	1.7 (grounded) 2 (aerial)
Captain Falcon	Rapid jab	9
	Dash attack	1.5
Charizard	Dash attack	1.5
Corrin	Rapid jab	8
	Forward smash	1.6
Daisy	Dash attack (hit 1)	2.9
Dark Pit	Rapid jab	3
	Dash attack	1.37
Donkey Kong	Hand Slap	0.58
Dr. Mario	Dash attack	1.875
Duck Hunt	Rapid jab	5
Falco	Rapid jab	5
Fox	Rapid jab	6
	Dash attack	1.8
Ganondorf	Dash attack	1.3
Greninja	Rapid jab	4
Hero	Kazap	0.3
Ike	Dash attack	1.2
Inkling	Rapid jab	6
	Dash attack	1.5
Ivysaur	Rapid jab	3
Jigglypuff	Pound	1.5
Joker (with Arsene)	Forward tilt (hit 2)	2
	Down tilt	1.5
	Dash attack (hit 2)	1.1
	Forward smash	1.25
	Up smash (clean)
	Down smash (hit 2)	1.33
Ken	Inazuma Kick	1.25
King Dedede	Rapid jab	5
King K. Rool	Dash attack (clean hit)	1.15
Kirby	Rapid jab	7
Link	Dash attack	1.4
Lucina	Dash attack	1.5
Mario	Dash attack	1.875
Marth	Dash attack	1.5
Mega Man	Dash attack (last hit)	2.1
	Forward smash	0.32
Meta Knight	Rapid jab	4
Mewtwo	Rapid jab	4
	Dash attack	1.3
Mii Gunner	Dash attack	1.5
	Bomb Drop (hit 1)	3.75
Mii Swordfighter	Forward tilt	0.7
	Dash attack	1.6
Min Min	Rapid jab	9
Mr. Game & Watch	Rapid jab	10
Mythra	Rapid jab	8
	Neutral aerial (landing hit)	0.2
	Lightning Buster (linking hits)	2
Palutena	Rapid jab	7
Peach	Dash attack (hit 1)	2.9
Pikachu	Dash attack	1.8
Piranha Plant	Rapid jab	9
	Dash attack	1.3
Pit	Rapid jab	3
	Dash attack	1.37
Pyra	Rapid jab	8
	Forward tilt	1.5
	Dash attack
Richter	Rapid jab	5
	Axe	1.1
Ridley	Rapid jab	5
	Skewer	0.2
Robin	Rapid jab	3
Rosalina & Luma	Rapid jab (Rosalina)	5
Roy	Dash attack	1.25
Ryu	Hadoken	1.2 (weak) 1.13 (medium) 1.06 (strong)
Sephiroth	Blade Dash	0.5
Sheik	Rapid jab	9
	Dash attack	1.5
Simon	Rapid jab	5
	Axe	1.1
Sonic	Dash attack	0.75 (clean) 1.05 (late)
	Homing Attack	0.5
Steve	Neutral attack	0.25
	Forward tilt
	Neutral aerial
Squirtle	Dash attack (clean)	1.45
Terry	Dodge Attack	0.5
Wii Fit Trainer	Dash attack	1.3 (clean) 1.8 (late)
Young Link	Rapid jab	6
Zelda	Rapid jab	8

External links

• Shieldstun canceling in Ultimate