How does Sekiro sync parry animations to enemy attacks?

Sekiro has multiple parry animations in response to different enemy attacks, but how does the game know which animation to play? Does the game detect which direction the attack is coming from via hitbox intersection and play a corresponding animation, or is each enemy attack labeled with a direction and that directional parry animations is played each time? For instance, two enemies both have slashes coming from the right, the attacks would be labeled something like "right attack" which would trigger the "right parry" animation every time it's deflected regardless of enemy.

I have no clue how to code so none of this might make any sense, I've just always loved Sekiro's animations and wonder how it all worked.