What Is Perfect Shielding
Though present in other games to some extent, perfect shielding in Super Smash Bros. Ultimate is unique as it is much more comparable to a parrying system. When one perfect shields an attack, the attacker is frozen in place for a few moments, while the defender will strike a pose and their eyes will begin to glow. This visual signal, along with the sound cue that plays, is an indication that the perfect shield was a success.
Once in this state, the defender has a chance to act sooner than the attacker, so while their opponent is still waiting for their attack's animation to play out, the defender can quickly follow up with attacks and set-ups of their own.
How to Pull Off a Perfect Shield
The timing for perfect shielding is a bit tricky. To put it in layman's terms, when an attack is approaching, a perfect shield requires the player to drop the shield button right before it connects.
To go into more detail, the attack must be blocked within the first 5 frames of the shield drop animation, which itself only starts after a shield has been up for at least 3 frames. Since the game goes through 60 frames in a single second, it's fair to say that the timing on this maneuver is strict, but it's not impossible and I'm willing to bet that you'll even unintentionally trigger this parry on the odd occassion.
It should be noted, however, that this move is a risky one to commit to. If a player were to mess up the strict timing, they have no shield to block the incoming attack: it'd be a direct hit. Thus, this move is rather advanced as it requires knowledge of the game's inner timing, character attack timing, and it requires players to recognize the attack patterns of their opponents, something that is hard to focus on in a heated match.
But, despite the difficulty of this move, there's no need to get too intimidated. Even if the prior mentioned frame data seems like a bit much, it's not as though you need to be counting every frame in your head. It's a matter of practice to understand the feeling and timing of the parry.
So, What Are the Best Ways to Practice Parrying?
To learn a new technique, it's best to start off slow and in a controlled environment. That's why I personally recommend going into the training stage, which is exclusive to the single-player training mode.
While you can pick whatever character you want to play as, I recommend picking an opponent whose move set you are familiar with. If you're new to the game and unsure of everyone, Mario is a well-balanced character with a straightforward move set that would make for good training.
Once in game, set the computer's character action to attack with either smash attacks or special attacks. The computer's behavior will be set to "Stop" by default.
By changing the computer's actions, they will repeat the same attack over and over again with consistent timing. Now it is up to the player to attempt to parry these attacks. Start with a full shield before you attempt to drop the shield and parry the attack. Then, hold the shield button for increasingly less time until your parry shield timing is a short as possible. It's best not to hold down your shield for too long, as the longer a shield is kept up, the more likely a player can punish this behavior by either using a move that can break your shield or by grabbing.
If you find it difficult to get the strict timing of parrying down, the training tool can also affect the speed of the game itself, so you can start off at running the game at one-half speed before easing yourself into a full-speed set.
Another method that can be used is by going to the far-left side of the training stage with your computer opponent. Once facing the wall, spawn in a green shell and throw it against the wall. When the shell ricochets off the wall, you have an opportunity to parry the blow and grab the shell immediately. The cycle can then be repeated to gain an easier understanding of the parry timing and Koopa shells can be endlessly spawned in.
Once a firm understanding of the timing has been established, the best way to practice parrying from then on out is to play against other players either in-person or online. If you every find yourself playing against someone who has an attack pattern you recognize, challenge yourself to punish them with a parry followed up by an attack, rather than simply blocking with your shield or dodging their offensive.
Perfect Shielding Multi-Hit Moves
Of course, not all moves that you'll be dealing with will be one singlular hit. Many characters have attacks, both melee and projectile, that deal damage consecutively rather than as a single clean hit. So, how can one go about parrying these attacks?
This is where it gets a bit tricky, so we'll start with an easier example: Robin's Arcthunder. This attack is a projectile that, upon making contact, deals consecutive hits to its victim, frame-by-frame. For attacks of this nature, as long as you perfect shield the first hit, the subsequent hits will automatically be parried as well.
If a move deals damage in a more spread-out fashion, rather than frame-by-frame, perfect shielding becomes a much harder task. The timing becomes much stricter and more variables, such as the shield-stun certain moves have, will come into play. It's still "possible", but the practicality of parrying a move with multiple hits comes into question.
As an example, let's use Corrin charging his side-smash. When he charges up this attack, his sword has a hitbox that continuously deals damage, but when parrying it, you can easily tell that this rate at which the sword will hit the opponent is much slower than Robin's Arcthunder. Because of this slower speed, you will have to press and release the shield button multiple times to parry each hit registered by the game.
When Is Perfect Shielding Not Ideal?
Normally, parrying is a risky move, so it's best not to be very reliant on it. It is especially unwise to use it against projectiles, however, as in some cases the action can actually result in more lag for the defender. While most projectiles do not have this consequence, the best-case scenario is that the user only obtains 1 frame less of lag wheras the attacker will be unaffected by the parry. Thus, you'd be using a high-risk maneuver for a likely low-value reward.
If your opponent isn't the type to use projectiles, however, it couldn't hurt to practice perfect shielding against them, and it can definitely come as a surprise if done consistently. For more precise information about perfect shielding, primarily frame data, visit the Smash Wiki at this link.