I can answer this, I used to theory about this a lot about a year and a half ago.
Anticipation is key.
I can give an example. When I play Ken vs Ken, my 2nd best matchup, versus most opponent players, I can easily punish dash ins with strong fierce, or if they low forward, I can reversal or if they jump, I can parry jump ins. This is because my anticipation tells me from previous matches that this is all the player can do, as in this is opponent players whole offense, if I limit this, they can’t win. Therefore, anticipation plus key word COMMITMENT. I commit to standing in dash distance, and I wait for either low forward, dash, or jump. Players always think, “Yi has really good reflexes, he can punish dash ins”. No my reflexes are average to above average at best, but my anticipation plus committing at right times make my reflexes look fast.
However, versus a better player, for example, Vinny is the best I’ve seen at reversaling low forward, but he can never reversal my low forward. He’s thinking about my other offensive moves that I do. Versus not as good Kens, I see him reversal every low forward. When I played MOV Ken Ken, he did not reversal every low forward or punish all my dashes. There are options to make players stop looking for it, but I won’t go into detail because I am keeping the community at a low level.
Assuming both players are capable of doing what I just mentioned, reversal SA3, punish dash in or punish jump in, the best option would be to walk forward slide back throw with Ken. (Of course in a high level matchup, this should not work more than 2 times, so don’t be satisfied with just this response, and I only know 1 other player in America who plays at this level). This only works at high level, as both players are respecting the other players ability, so they won’t hit a button knowing it’ll get reversaled, or they won’t dash knowing it’ll get punished.
A good player has many more ways of getting in then just dash, low move or jump. When I first theorized about this, I could only commit to 1 option, for example looking for the low forward but I would get hit by dash throw. Now I am able to multi commit. I think MOV can commit to maybe 3-5 different defensive options based on opponent player.
Oh yes, Denjizz is right, he practices very hard. And no, not everyone can achieve this.