Memories are just one way you can upgrade your attack in Sekiro: Shadows Die Twice. You can also upgrade with the help of the Mask. Unfortunately it’s split into three pieces and requires you go for a bit of Shinobi style fishing, and the merchants are particularly picky about how many scales are needed to buy the pieces from them.
[cms-block]There is now a dedicated [cms-block] where you can find tips for the many bosses of the game.