Sekiro Great Shinobi Owl no damage run strategy 

New strat. This was done with atk power 6 (where you'd be on a no damage run). The trick to getting the first phase done quickly is getting good spacing on the mortal draw hits. You want to be far enough away that both with hit unguarded, but not too far away otherwise the hits don't do as much posture damage (weird) and Owl will deaggro, making his posture bar drop quickly. For second phase you should have a bit of a delay on the third slash, but not too much otherwise you'll get hit by the occasional kick. Overall the strategy is pretty safe and easy with a small bit of practice, and it's insanely fast.