Frame advantage starts rushdown. Rushdown is pressuring your opponent with plus on block attacks and throwing them when they block. If they decide to attack instead of blocking, you'll interrupt them because you have the frame advantage. The mixup of rushdown is not about which direction to block, instead it's about when to block and when to stop blocking.

Here's how to calculate when your attack will hit after a frame advantage. Take the frame your attack hits and subtract frame advantage. If my attack hits on the 7th frame and I'm at a frame advantage of +3, my attack will hit 4 frames before my opponent can perform an action. It is essentially an attack that hits on the 4th frame.

A string is a series of attacks and a blockstring is a string that is useful on block.

Frame Trap

A frame trap is a blockstring with an intentional gap to counter hit your opponent if they retaliate with an attack. Let's do some math to create a frame trap. Sasquatch's fastest attack hits on the 6th frame. I want a blockstring with a gap of 5 frames or fewer without going into a negative number. I'll start with B. B. Hood's basket attack because it's +6 on block. I can use an attack that hits on the 11th frame because 11 – 6 is 5 and that makes the attack active 1 frame before Sasquatch's 6 frame attack.

You can beat frame traps by simply blocking and waiting your turn. Or if you have an invincible attack you can use it to beat the frame trap.

True Blockstring

Here's some more math. B.B. Hood's basket attack is +6 on block. Her crouching light punch hits on the 5th frame. If I do the math 5 – 6 is... -1. Negative startup? A negative number means Sasquatch is still in blockstun when crouching light punch becomes active, guaranteeing it connects. This is a true blockstring. The defender is locked in blockstun and cannot perform any action until they've left blockstun. Sasquatch cannot even perform an invincible attack to escape. He's forced to block crouching light punch.

Absolute Guard is the state that automatically blocks attacks for the character while they're in blockstun. The player can even let go of blocking and the character will continue to block until they've left blockstun.

You might be wondering how a true blockstring can be a mixup if the game automatically blocks attacks during blockstun. A true blockstring is a mixup because the attacker is guaranteed a number of hits but they can end the blockstring early and perform a different action.

This is a true blockstring. The first hit is a projectile and the next four hits are punches. If the projectile is blocked, the entire five hit blockstring is guaranteed. There is nothing the defender can do but wait for the true blockstring to end.

The attacker can:
Perform five hits of the true blockstring.
Perform four hits of the true blockstring then attack high, attack low, or throw.
Perform three hits of the true blockstring then attack high, attack low, or throw.
Perform two hits of the true blockstring then attack high, attack low, or throw.
Perform one hit of the true blockstring then attack high, attack low, or throw.

Three Elements of Rushdown

There are three elements of rushdown. Frame trapping is the first one. The attacker does a plus on block attack and if the defender retaliates, even with their fastest attack, they get interrupted.

You might be wondering why the defender would ever attack at a frame disadvantage. If the defender decides to wait and block this might happen.

The attacker continues their pressure by walking forward. This can go on forever unless the defender interrupts the walk forward with an attack. Walking forward is the second element of rushdown.

Or if the defender decides to wait and block this might also happen.

The defender gets thrown for blocking. A tick throw is a throw that immediately follows an attack. Tick throwing is the third element of rushdown.

From the attacker's perspective: Walk forward to continue pressure. Tick throw to beat blocking up close. Frame trap to beat attacks.

From the defender's perspective: Attack to beat walking forward. Attack to sometimes beat tick throws. Block to beat frame traps.

Don't always use frame advantage for guaranteed attacks. When I feel my opponent is scared and won't retaliate, I perform a slow high attack or slow low attack for a mixup.

Don't get too obsessed with making sure your numbers are perfectly tight. Remember that your opponent is human.

There are two quotes you need to live by in fighting games:
“Any attack can be plus on block if your opponent is scared.”

“Hesitation is the best type of frame advantage.”

As the defender you have to force yourself to attack at a frame disadvantage at times. Abare is the Japanese word for attacking from a frame disadvantage. There are a couple of reason why you would do this.
1. Your disadvantage isn't that much.
2. You predict your opponent isn't going to do a guaranteed attack. If your opponent does a slow attack and you do your fastest attack you might be able to interrupt them.
3. You have better options than your opponent at this range even with the frame disadvantage.

Because characters are wider when they crouch you may be able to add an extra hit to your blockstring if your opponent crouch blocks. The fourth hit whiffs when Blanka stand blocks but connects when Blanka crouch blocks.

When I learn a game or character I set the training dummy to alternate between stand block and crouch block to see how it affects my blockstrings. I set the training dummy to Guard All and Switch Guard Direction to Random. My blockstring is standing light punch, standing medium kick, and crouching medium punch. If my opponent crouch blocks crouching medium punch I'll combo it into stomp and it'll add another hit to my blockstring.

Adding another hit to a blockstring doesn't sound significant but try to think of it as adding another guess in a row instead of adding a single hit.

If I flip a coin you have a 50% chance of guessing all the flips correctly.
If I flip two coins in a row you have a 25% chance of guessing all the flips correctly.
If I flip three coins in a row you have a 12.5% chance of guessing all the flips correctly.

I feel like mixing things up.