Discuss FromSoftware's Sekiro: Shadows Die Twice
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I'm not sure if this is helpful for anyone, but I found that you can get his first phase down instantly using a yashikura's sugar and mid air mortal draw twice. He sometimes survives but when he does he has one or two hits left before he's down. This leaves you with one phase to deal with and only down one gourd (for the healing once the sugar wears off).
It worked for me. Now I just have to find a way to beat his second phase /:
Bloody Owl of Hirata
On his regular slash combos, don't counterattack unless he does the double-slash. Instead wait for him to finish the combo, which is usually either the firecrackers which you can run around counterclockwise to hit him in the back, or a sweeping attack which you can jump back-left to land on his head. The extra easy deflects help build up his posture a little faster