Ultra Street Fighter IV/Game Systems
Whenever you strike the opponent during the Startup Frames of their moves, you will score a Counter Hit. Whenever you land a Counter Hit, you will earn a damage bonus. Whatever the damage that was going to be done by that hit will get a 25% boost. So if you hit the opponent with a move that does 100 damage, as a Counter Hit it would do 125 damage. But keep in mind that if you continue to combo the opponent after that first hit, only that first hit will gain the damage boost. The rest of the hits will do normal damage.
Counter Hit Benefits
Not only do you get more damage, but more importantly, your move will get an additional bonus to the Hit Stun the move causes. For Light Attacks, you gain an extra 1 frame of Hit Stun. For Medium and Hard Attacks, you gain a 3 frame Hit Stun bonus.
It's this latter bonus that turns out to be really important. While 3 frames, which equates to only 1/20th of a second, doesn't sound like much, it's actually a fairly significant amount. It opens up a lot of combos that are not possible without Counter Hits, so high level play has actually evolved to use setups to fish for Counter Hits that allow the player to land more damaging combos (see Frame Traps section in Advanced Techniques and Concepts).
One thing that has helped with taking advantage of Counter Hits is that the very instant you connect one, the words "Counter Hit" appear under your character's name almost instantaneously. It actually is a very good trigger to react to. If you ever press a button and are looking for a Counter Hit to react to, after hitting your button, do not look at the characters anymore, look for the "Counter Hit" message to appear.
For example, on Counter Hit, Cody's towards medium punch can link into Last Dread Dust. So as soon as you hit towards medium punch, stare right under Cody's name. You can react to the words appearing and activate the Ultra if you land the Counter Hit. And, if it is just a regular hit, not seeing the words will let you know not to let the Ultra rip.
You can even practice this very easily in Training Mode thanks to the Counter Hit option in the Training Menu. You can turn Counter Hits "On," "Off," or -- and this is the important one -- "Random." By setting it to random, it's very easy to practice fishing for and properly reacting to Counter Hits.
Aerial Counter Hits
If you Counter Hit someone out of the air, the only added benefit you get is the extra damage. Since there is no Hit Stun in the air, there isn't any Hit Stuns to increase.
Counter Hit Exceptions
Projectile moves only reward you a Counter Hit if you hit the opponent before the Projectile is produced. Some moves cannot be Counter Hit at all because invincibility frames cover up all of the Startup Frames. Thus, the move can never be hit in Startup. Zangief's Double Lariat and Rufus's EX Messiah Kick are two examples of this.
Focus Attacks aren't the only moves in the game that have the ability to absorb a single hit in Ultra Street Fighter IV. There are a few other moves that are considered "Armored." The behavior of these Armored Moves are nearly identical to a Focus Attack during the Focus Phase (see Focus Attack in Universal Abilities).
They have the ability to absorb a single hit during the move. For example, if you perform Balrog's EX Dash Straight, which has Armor, you can plow right through something like Ryu's Hadoken or a Crouching Medium Kick from Ken and nail the opponent. Of course, if you get hit by more than one hit, you will be knocked out of your move. When you absorb the attack, you take the damage the move would have given in White Damage instead of regular damage. And Armored Moves lose instantly to Armor Breakers.
Examples of Armored Moves are Balrog's EX Dash Straight, Abel's EX Change of Direction, Zangief's EX Flying Power Bomb, and Gouken's Kongoshin. Some other moves technically have Armor, but have slightly altered behavior. Juri's Kasatushi has all of the behavior of an Armored Move, but she does not take any White Damage or regular damage. Dudley's Cross Counter also behaves like an Armored Move, except he takes the regular damage immediately upon hit instead of taking White Damage. And lastly, El Fuerte's Habanero Dash (both the forward and backward versions) and Guy's EX Run actually have the ability to absorb two hits instead of one.
Earlier in this guide, in the Focus Attack and Armored Moves section, the concept of "White Damage" has already been mentioned, but to this point it has not yet been described what White Damage is exactly. It's a relatively new concept to Street Fighter, though something very similar to it has been used in Vampire Savior long ago.
Anytime you character takes "White Damage," what happens is that, in your Life Meter, your energy will drain but, instead of your Life Meter completely disappearing, the part that got drained gets replaced by a white, flashing section in the Life Meter that is referred to as "White Health." What this White Health represents is a chunk of life that you have technically lost but still have the ability to recover back.
The only way to recover this chunk of White Health back, however, is time. Whenever you take White Damage, your meter will be stagnant for about 1 second on the clock. After that 1 second has passed, you'll start to see the White Health in your Life Meter gradually convert back into regular health starting from the section closer to the K.O. mark up to the place the White Health stops.
Also, you can repeatedly continue to take more and more White Damage. If the opponent, for example, chucks Hadokens at you from across the screen, you can Focus them over and over. You'll take White Damage from each of them and the White Health you have will just continue to grow larger and larger as you keep taking White Damage. But that means you just have that much larger of a chunk of White Health to recover back, and the recovery rate is slow and remains at the same pace the entire time.
Losing White Health
However, there is one problem with White Health: if at any point in time you are hit by a move before your White Health fully recovers, you will not only take the normal damage you would have starting from where your regular life is, you also lose the entire chunk of White Health instantly.
So let's say you have 1000 Hit Points and take 100 points of White Damage. If you get hit by a move that does 150 damage before you recover any of that White Health, you'll lose the entire 100 points of White Health and take the 150 points of damage from the move as well to leave you at 750 health left. So if you see that you have a lot of White Damage in your Life Meter, it's best to play a bit more careful to try and recover as much life as possible.
And so while it may seem like a good idea to sit back and Focus projectiles from your opponent a bunch of times to gain Ultra Meter, you have to be careful: absorb three or four Projectiles in a row and then get hit by one Crouching Light Kick, and you'll lose all of that life in one hit if you haven't recovered any back yet.
There's one more catch with White Health: you can't turtle up and start playing super defensively once you have White Health to recover your life safely. This is because any time you Block a move, and this is any move, the recovery on the White Health is halted wherever it happens to be at. And remember that 1 second you had to wait before it started recovering the first time? You now have to wait that second once again before it starts recovering again. And every time you Block a move, this happens, so if your opponent rushes you down properly, you will never gain back that White Health. The best ways to ensure your White Health gets filled up again is to either run away really well or start attacking your opponent instead so they can't hit you or force you to Block anything.
No Life Left Scenarios
So there are a couple of important questions to ask about White Health. The first obvious one is: if you have 90 health left and you Focus an attack that does 100 damage, will that kill you since you didn't have enough regular health left to absorb the entire 100 points of damage?
The answer is no, actually. Well, not in this particular case. It really depends. See, the way White Damage works in this game is that, if you happen to not have enough life to absorb a hit fully, the health that you were short on starts getting removed from your White Health.
So here's an example to help clear this up. Let's say you just happen to have 76 hit points left in your Life Meter. You opponent now attacks you a move that does 200 damage. Well, just so that we are technically accurate, remember that your Life Meter is already in its last 15%, so that means you are taking only 75% damage of that 200 damage move, so now the move is doing 150 points of damage.
However, you don't get hit by the move, you end up Focusing it. What happens here? Well, first off, all 76 health points you have will be turned into White Health by the White Damage. But what happens to the other 74 points of damage leftover from your opponent's attack? It starts getting subtracted from your White Health. You have 76 point of White Health right now, so the 74 remaining points of damage will bring that down to only 2 points of White Health. And because you still have even that tiny amount of White Health left, you are technically still alive so the game will not count you as K.O.'ed just yet.
So to sum it up properly, in order to die from taking White Damage, the move that hits you needs to take off 200% or more of life you have left. If you have 50 life left, only a 100 or more damage hit will K.O. you if you absorb the move. If you have 100 health left, only a 200 or more damage hit will K.O. you. And on and on.
And this is why it's so hard to kill with Gen's Mantis Mode Ultra II: the Shitenketsu. It does a measly 23 hit points of damage on the first hit, then 420 points of pure White Damage. So in order for an average opponent of 1000 Hit Points to be killed by the move, they must have only 210 life left. The 23 points of damage at the start gets damage reduced to 21 (because they are in their bottom 30% of life), leaving the opponent with 189 health left. The 420 damage hit gets damage reduced to 378 damage. 189 of that gets turned into White Damage, leaving the remaining 189 to get drained by the remaining damage.
White Health and Chip Damage
Another question is how does Chip Damage affect White Health? When you have White Health left and you take any Chip Damage from a Special Move or Super Combo or Ultra Combo, the Chip Damage is actually taken off of your White Health. You don't lose the whole chunk of White Health, just whatever amount the Chip Damage was normally going to do.
Jumping is jumping, right? Not much more to say about it? Well, if everything in a Street Fighter game was that straight forward, guides like this wouldn't need to exist.
Whenever you perform a Jump, it actually takes four frames for the majority of the cast to actually get off the floor. These four frames are typically referred to as "Pre-Jump Frames." If a character is hit during these four frames, they will actually remain grounded so that any ground combo will connect fully on them. However, during these Pre-Jump Frames, you cannot be Thrown. So if you start jumping the very frame something like a Spinning Piledriver would connect on you, you will escape and the Spinning Piledriver will whiff.
Also, the character performing the Jump is allowed to cancel these Pre-Jump frames with and only with Special Moves, Super Combos, and Ultra Combos. This gives you leeway when performing Quarter Circle Forward motions and accidentally hitting Forward Flip at the end of the Special Move code. You'll start to Jump, but if you hit the button early enough, the Special Move takes precedent over the Jump during the Pre-Jump Frames.
Again, most every character has 4 Pre-Jump Frames. The only ones that do not are:
Two characters also have a High Jump (or Super Jump, as some call it): C. Viper and Ibuki. High Jumps actually have slightly modified behavior than regular Jumps. First off, you can actually be thrown out of the last 3 Pre-Jump Frames -- only the first Pre-Jump Frame cannot be Thrown.
Secondly, there is a small window right after the High Jump where no actions can be performed. When you High Jump and try to perform a Normal Move the instant you leave the ground, you'll notice you have to wait ever so slightly before a Normal Move, Special Move, Super Combo, Air Throw, etc. can be performed.
C. Viper, however, has one strange exception: the Pre-Jump Frames of her High Jump can actually be canceled by a Focus Attack. Even her regular Jump cannot have their Pre-Jump Frames canceled by a Focus, only her High Jump allows this. Ibuki does not have this ability.
Land Frames / Trip Guard
So that was Jumping on the way up. Now, how about on the way down? This is where the discussion of a concept known as "Trip Guard" comes into play. It's a term that has been used since the very first Street Fighter II, and has played an important role in Street Fighter games since then. It's basically the concept of being able to Block any moves upon landing, most notably Sweeps (thus the term "Trip" Guard).
In the old school games of the Street Fighter II series, Trip Guard was not possible. The opponent could always hit you the first frame you landed from a Jump. Later on, in the Street Fighter Alpha Series, for example, they added Trip Guard and allowed the character to always Block attacks the instant they landed.
However, in Ultra Street Fighter IV, it's not as simple as just saying if Trip Guard exists or not. It's actually a little more complicated now and a more beneficial to study the Frame Data of a Jump upon landing.
After the Jump
Just like how there are four Pre-Jump Frames at the start of the Jump, every character has four "Landing Frames" when they land from a Jump. However, how these four frames behave really depends on one factor: whether or not you perform a Normal Move during your Jump.
First of all, regardless if you attack in the air with a Normal Move or not, the Landing Frames will always prevent you from performing any form of basic movement. You cannot cancel the Landing Frames with a Dash, a Crouch, or another Jump. However, you can always Tech Throws during your Landing Frames.
However, you are allowed to cancel all four Landing Frames with pretty much anything else if you do not perform any Normal Moves during your Jump. Special Moves, Super Combos, Focus Attacks, Throws, and even Normal Moves can all be performed the instant you land. And most importantly, you can Block during the Landing Frames. That means if you do not press a button in the air, you cannot be punished when landing from a Jump even if the opponent makes you land into their attack.
So what happens if you do perform a Normal Move in the air? If you do, the first two of the four Landing Frames are actual, genuine delay frames. You cannot do anything during these two frames, not even Block (though you can Tech Throws, still, as mentioned earlier). Thus, opponents can punish you upon landing. However, the last two Landing Frames grant you the ability to Block, you still cannot perform a Special Move or a Super Combo or anything during those two frames.
Aerial Special Moves
With regards to performing Special Moves or Super Combos or Ultra Combos in the air, Landing Frames are technically ignored. Once you perform a Special Move, Super, or Ultra in the air, those moves come with their own delay frames that is unique and specific to that move.
Empty Jump Into Specials
There must be something said about being able to do anything on the first Landing Frame of an Empty Jump (Empty Jump being a Jump where you don't perform any moves in the air). This sounds really useful, especially being able to do Supers and Ultras the instant you land. But you'll find in practice that, oftentimes, when you try to perform one of these the instant you land, you lose out to your opponent's attacks a lot... even though you didn't do a Normal Move in the air at all!
There actually is a reason for this. Most of the time, especially in a game like Street Fighter IV where the Input Window for most actions is so large, our natural tendencies is to press buttons early. For example, while getting up from the floor, we know we can start hitting the buttons for the Special Move before we actually get up and still get the Reversal.
So when trying to perform a Special Move right when you land from an Empty Jump, we tend to do the motion for the move and start hammering on the button to do the Special Move... before we land. So let's think about this carefully. What happens when we do this? What you don't actually see happens is that, because you press the button for the Special Move right before you land, you actually activated a Normal Move in the air! That means, even though the Jumping Normal Attack only comes out for 1 or 2 frames before you land, the Landing Frames behave as if you did a Normal Move and not as if you performed an Empty Jump! So now you have two true delay frames at the instant you landed.
In other words, to actually perform a Special Move or Focus Attack or Super Combo or whatever the instant you land from an Empty Jump, you have to be frame perfect with your timing and press the button(s) the very frame you land. Any earlier, even by one tiny frame, and you give yourself two delay frames upon landing.
Once again, we have to talk about the High Jumps of C. Viper and Ibuki. Interestingly enough, if you do an Empty High Jump, you actually have 11 entire frames of delay upon landing. You can't do anything here, not even Tech a Throw! You are basically entirely vulnerable for all 11 frames to anything the opponent wants to dish out to you. However, if you perform a Normal Move in the air, you actually have the same recovery as you do when you perform a Normal Move during a regular Jump. So it actually turns out you have less delay and are safer if you perform a Normal Attack in the air during a High Jump.
Wake-Up Frame Data
Every time a character is knocked down and they either choose not to do a Quick Stand or are not able to do a Quick Stand (after a "Hard Knock-Down"), every character takes a moment before they get up. However, the time it takes for every character to get up off the floor is NOT universal and is very slightly varied. Also, the timing depends on whether the character is knocked down in a face down position or a face up position! When knocked down face up, characters generally take a bit longer to get up.
Also, Gen (both face up and face down) and Adon (only face down) have a strange glitch where, if they don't perform any actions immediately after getting up, they are invincible for one extra frame. This really isn't useful at all as 1 frame is too small to make a huge difference, but it's just noted here for posterity's sake.
Here are the exact frame counts of each character's wake-up times:
In all past Street Fighter games, when you held down on the joystick to make your character crouch, the very first frame the game detected your joystick at down, your character was considered crouching that very first frame.
This is not the case in Street Fighter IV.
Trying to crouch has a strange problem of needing a "transition period" between Standing and Crouching in this game. This is what is referred to by Crouch Delay. It actually takes a few frames to officially be Crouching after hitting any of the three down positions on the joystick. And during these transition frames, you really have the worst of both worlds all at the same time.
First of all, you are still considered "tall" in the sense that moves that would normally whiff if you were fully Crouching actually connect on you. Secondly, you are considered in a Standing state, so moves like Hakan's Oil Dive, which only grabs Standing characters, will work on you. Thirdly, you are actually considered in Crouching state at the same time! Thus, any moves that must be Blocked high, like a Jumping Attack, will hit you if you are trying to Crouch Block! You really do have a huge combination of weaknesses during this transition.
Let's give some examples of each of these. If you are facing off against a Sagat and he knocks you down with a Light Punch Tiger Uppercut, he can throw a High Tiger Shot timed just right so that it'll be right above your head when you get up. Now, when you get up from off the ground, the game checks if you are holding down on the controller or not. If you are, the very first frame after you get up off the ground is one of these Crouching transition frames. So even though you can normally crouch right under a High Tiger Shot, because you are considered tall during the transition frames, you'll actually end up blocking the High Tiger Shot on the first frame you get up off the ground. But notice something odd: you'll end up Blocking it in a Crouching Block position! So, again, the game knows that you are crouching but you are still treated as tall so you still Block the High Tiger Shot!
You'll also notice this against Sagat a lot when you are just fighting him and he Throws a High Tiger Shot. You'll walk up and try to crouch under the High Tiger Shot at the last second, but you'll end up Crouch Blocking it instead. This is also caused by the Crouch Delay.
For a second example of this, if Cammy performs a Forward Throw on you and performs a Medium Punch Hooligan Roll the instant she recovers from the Throw, her Fatal Leg Twister can grab you the first frame you wake up. Normally, this move cannot grab characters who are crouching. But if you hold Down on the controller when you get up off the ground, she can still grab you anyhow. In the last example, we noted that the game knows you are Crouching, but it doesn't matter: the game apparently also registers you as still in a Standing state so you get grabbed by Cammy!
And lastly, to make matters even worse, let's look at a situation where you are facing off against Adon. Let's say you are Ryu, for example, and Crouch on the ground. If Adon walks up to you and does a Neutral Jump with an immediate Hard Kick, he cannot hit you. The Hard Kick comes out a fraction too slow to reach low enough to hit you while Crouching.
But now, let's change the scenario. Have Adon jump at you and perform a deep Jumping Medium Kick on you and make sure you Block it successfully. Right when Adon lands, have him perform that same Neutral Jump with the immediate Hard Kick. If you try to Crouch Block after Blocking the Jumping Medium Kick with Ryu, the Neutral Jump Hard Kick from Adon will actually hit you!
Let's think about how crazy this is. Like the Sagat example, you are still considered "tall" while in the Crouching transition frames which is why the move can actually reach you. But since it's a Jumping Move and the game also registers you as Crouching, you actually end up getting hit by the Hard Kick because you are Crouch Blocking. It's a method by which some characters can land "instant Overheads" with their Jump Attacks that normally wouldn't connect. Many people refer to this as a "Fuzzy Guard" but that term doesn't really make much sense, so it will not be referred to that in this guide.
There is one very odd thing about this, however, that I cannot explain. In the situation listed above, with Adon performing the Jumping Medium Kick into Neutral Jumping Hard Kick, if you, as Ryu, do not Crouch Block after the Jumping Attack and just hold straight down or Offensive Crouch, Adon will miss! I'm not really sure why this happens, but it does. Technically, while crouching, you should be "tall" enough during the transition frames so that you get hit by the Hard Kick no matter how you Crouch, but it doesn't happen here. In the example for Sagat, listed above, you'll get hit by the High Tiger Shot if you hold straight down or Offensive Crouch. The only real explanation is that, while holding Defensive Crouch, going into Block animation keeps you slightly taller than not going into Block animation and the Meaty High Tiger Shot from Sagat is just too Meaty.
Combating Crouch Delay
There actually is a way to counter this problem. In the second example listed above, where Cammy grabs you with the Hooligan Roll, you can actually escape the situation without needing a Reversal or a Back Dash or anything. The trick is that if you press a button during the transition frames between Standing and Crouching, you'll go instantly into your Crouching Attack. This will also instantly shift you to a fully Crouching state. So if you can time a Normal Move the first frame you get up off the ground, you can avoid the Fatal Leg Twister from Cammy's Hooligan Roll.
And as previously mentioned, it can be really frustrating when you are trying to squeeze past High Tiger Shots and you end up getting put into Block Stun and getting pushed back because you ended up Crouch Blocking them. You can actually avoid this by hitting Light Punch the instant you crouch, so that you end up crouching instantly. So at the last second, if you hit Defensive Crouch and Light Punch (or Light Kick, whichever move puts you in the least delay), you'll end up successfully crouching under the High Tiger Shot, even at the last second.
Facing the Wrong Way
Lastly, only in the case of getting up off the ground, the Crouch Delay transitions frames are actually bypassed if you happened to be knocked down so that, when you get up, you get up facing away from the opponent. These are the situations where, while on the ground, you are on your back with your head pointed towards the opponent or on your stomach with your feet pointed towards the opponent. The reason for this is because this causes you to get up with your back facing the opponent, and for some reason the act of turning around while holding down on the controller will also cause your character to crouch instantly.
Many of the past games in Street Fighter history have had moves that are designed to pass through Projectiles. However, in the past games, this was usually done by Hitbox manipulation. Projectiles only hit in a small range and most moves designed to go through Projectiles had the areas at where they could be hit altered so that they avoided that small range.
In Street Fighter IV, however, the developers decided to take a much more direct route. Projectiles are considered their own property and moves are assigned that property in order to be considered a Projectile. Moves like Ryu's Hadoken and Guile's Sonic Boom are obviously given the Projectile property, but other moves like C. Viper's Seismic Hammer, M. Bison's EX Psycho Crusher, Rose's Soul Satellite, and Chun Li's Kikosho are all moves that contain the Projectile property.
Projectile Invincible Moves
Because they now have moves that are tagged with this property, it makes it that much easier for them to tag moves with a counter "Projectile Invincibility" property. This allows moves to be able to pass through Projectiles without having to fiddle with Hitboxes at the risk of affecting how they behave in relation with other attacks.
Examples of moves with the Projectile Invincibility property are Zangief's Double Lariat, Blanka's EX Rolling Attack, T. Hawk's EX Condor Spire, and Rufus's Big Bang Typhoon. These moves will pass through any move considered a Projectile. For example, if Chun Li performs her Ultra II, the Kikosho, Zangief can perform the Double Lariat and slide right through it and hit her. Blanka can just EX Rolling Attack right through it and hit Chun Li. Rose can activate Soul Satellite and if Rufus activates the Big Bang Typhoon, he can just slide right into Rose and the entire time Rose is blocking the Ultra, the Soul Satellites will just spin right through Rufus. And if M. Bison does the normal Psycho Crusher vs. T. Hawk's EX Condor Spire, the characters will trade hits. But if M. Bison does the EX Psycho Crusher, which now has the Projectile Property, T. Hawk will beat M. Bison every time.
It's important to know which moves count as Projectiles and which moves have Projectile Invincibility. Knowing things like the initial dirt spray from Cody's Last Dread Dust Ultra or the first hit from C. Viper's Burst Time Ultra count as Projectiles could help you avoid those moves with your own Projectile Invincible moves.
Every game has it: a method of preventing combos from doing too much damage. Ultra Street Fighter IV's method is very straight forward and very easy to calculate and it shows how easily long combos are severely diminished in damage.
Move Based Not Hit Based
Before we get into exactly the numbers of Damage Scaling, one concept needs to be established. In past games, a lot of the Damage Scaling comes from the number of hits in a Combo: as the Combometer gets higher, the less damage each hit does. Thus, moves that do a lot of hits tend to cause the Damage Scaling to kick in quicker, which usually meant that moves that did a lot of hits were generally not good for damage.
This is not the case in Ultra Street Fighter IV. They actually figured out a clever way to avoid the pitfalls of going by the Combometer. Instead of going by hits, they decided to calculate Damage Scaling by moves. The more number of moves used in a Combo, the more the later moves start to get scaled. So regardless of how many hits a move does, it only receives the scaling once.
The way the game registers what counts as a move in the scheme of Damage Scaling is pretty simple: anytime a button must be pressed to perform a hit, it counts as a move.
So a move like Ryu's Standing Hard Punch counts as one move. Vega's Close Hard Punch, which hits twice, counts as one move. Honda's Hundred Hand Slap, all 7 hits, count as one move because, although you have to hit 5 punches successively, only the last one actually activates the Special Move. Dudley's EX Machine Gun Punch counts as one move even though it hits 7 times. Even Seth's Hard Kick Hyakuretsukyaku, which hits 17 times, counts as one move.
However, Ken's Target Combo of Medium Punch into Hard Punch counts as two moves because there are two button presses that both activate hits. Guy's full Bushin Gokusaken counts as four moves because you have to hit a button for all four hits of the chain. Fei Long's Rekkaken, when you perform all three hits, count as three moves. And as ridiculous as it may sound, Gen's Hard Kick Gekiro, when you get all 8 hits, counts as 8 separate moves because it requires 8 buttons presses to get all 8 hits.
So now that we've established what counts as a move, Damage Scaling follows a really easy formula. Also, please note that any Damage Scaling that occurs due to how much life is left in the Life Meter will be ignored for the rest of this section.
The first two moves of a Combo will always do 100% of their damage. The third move of a Combo will do 80% of its damage. The fourth move will do 70% and each successive move from that point always drops another 10% until it reaches the minimum of 10%. Damage Scaling will never drop a move below 10% damage. And any hit has to do at least a minimum of 1 point of damage. You'll never find a situation where a move gets so scaled that it does 0 points of damage.
Damage Scaling Chart
So here's a handy chart that shows you what the damage scaling is:
Note: Minimum damage possible from a hit is 1 point.
So this is a good indication of just how quickly moves can be reduced in damage. Any Combo that starts off with lots of Light Attacks will start reducing damage quickly. For example, Sakura can do two Crouching Light Punches into a Standing Light Punch linked into a Crouching Medium Kick canceled into a Hard Punch Shouoken. By the time the Crouching Medium Kick connects, it's the fourth move in the combo so it's already doing 70% damage! And by the time to Shouoken is hitting, it's already doing only 60% damage. It's definitely better to get a lot of the stronger hits up front, otherwise your combo could end up very weak.
Focus Attacks and Ultra Combos
There are a couple of exceptions, however: Focus Attacks (regular and EX) and Ultra Combos. Both of these attacks will count as two moves in the equation of Damage Scaling. And for Focus Attacks, this is regardless of what level Focus Attack you perform.
That means if you perform a Combo such as Ryu's Close Hard Punch canceled into a Hadoken. The Close Hard Punch, being the first move, will do 100% damage. The Hadoken, the second move, will also do 100% damage. However, if Ryu performs a combo where he cancels Close Hard Punch into a Level 1 EX Focus Attack, the Close Hard Punch will do 100% as the first hit, but the EX Focus Attack will instantly be counted as two moves. So when it connects, it will count as the third move in the combo, not the second, and thus only do 80% of its damage. Another example would be if Rufus catches the opponent out of the air with his Jumping Hard Kick and Juggles the opponent after he lands with the Space Opera Symphony. The Jumping Hard Kick, even though it is two hits, counts as the first move and will do 100%. But the Space Opera Symphony will count as two moves and thus register as the third move and do 80% damage.
That means a Focus Attack and Ultra Combo can only do 100% of their damage if they connect as the very first move of a Combo. When they connect, they will automatically be registered as the second move, but the second move still does 100% damage. But if you ever do any move beforehand that does damage, they will be, at minimum, the 3rd move of a Combo and automatically do only 80% damage. And that also means that landing the Crumple Stun off of a Focus Attack and going directly into an Ultra instantly scales the Ultra damage down quite a bit. The Focus counts as the second move, which will do 100%, but the Ultra will now count as the fourth move and only do 70%!
This is why sometimes you are better off not landing an Ultra Combo at the end of a very long combo. For example, you'll see a lot of Balrog players not Juggle with his Ultra I after performing a long combo. Let's say a player performs the Combo of Crouching Light Punch, Crouching Light Kick into EX Dash Upper linked into another Crouching Light Punch, Crouching Light Kick into Buffalo Head. That's already six moves. He can Juggle with the Violent Buffalo at this point, but since it'll instantly count as the eighth move in the combo, it's only going to do 30%. And by that point, unless you just need that tiny bit left to finish someone off, it's just not worth doing it.
No Damage Moves
It should be noted that moves that deal absolutely no damage do not add to the scaling of the combo. However, as of Ultra Street Fighter IV, only the initial hit of grabs that trigger the throw animations do 0 damage. Moves that used to deal 0 damage were Fei Long, Yang, and Yun's command throws and Gouken's back throw. Since you would be landing a free combo after these throws, it made sense to Capcom to nerf them all by making them do 1 damage so they now make the combo scale down.
Everything Is Scaled
Damage isn't the only thing scaled during combos, however. Two more things are affected by the same scaling that damage is: Stun Damage and Super Meter gain. So the longer your combo goes on for, the less and less Stun you'll deal to the opponent and the less and less Super Meter you'll gain from the moves connecting on the opponent. Both of these follow the exact same formula as damage, with the 3rd hit reducing to 80% and each hit thereafter reducing by another 10%.