How do you counter a dan who spams that annoying tatsu thing?
He’s at a disadvantage on block after the mk or hk one. Do a jab or throw afterwards. It’ll beat everything he does besides DPs/ultras.
As for the lk one… he’s plus on block and therefore at an advantage. The best answer is backdash after blocking, but that’s not perfect.
If he does the mk or hk one from farther away you can ultra, DP, or even tag it with most normals with good timing. Test it in training.
block & punish.
Depending on who your character is, you have different options.
I found that Ken’s Light Super will always connect after any of Dan’s kicks. Experiment and figure out what works.