Height of Technique XP farm

Stealth-killing a single mob for 2104 exp and doing a quick reset. 12 seconds for the loop, resulting in ~10500 exp per minute. Numbers are from NG+.

Prerequisites

You need to be in a third-stage Ashina Castle, accessible after you kill the Divine Dragon.

You also need to have an Ashina Castle Upper Tower - Antechamber idol unlocked - this is the one right after you zip into the window of the big building that you later fight Genichiro on.

The Killing Part

Again, the idol to warp to: Ashina Castle, Upper Tower - Antechamber.

Go up the stairs and destroy the wooden/paper wall (is that what they call shōji?). There is a purple shinobi standing right behind it. Murder him. Resting on an idol will not reset the walls, they will still be broken, which is convenient.



And that's what you'll be doing: rest on a bonfi idol, then simply sprint to the shinobi, while getting slightly behind him, perform a stealth kill, repeat.

Bathe in Your Earnings

This will net you 2104 exp per kill if you're in NG+, and one cycle took me 12 seconds, so you're looking at ~10500 exp per minute.

I know you've always wanted to spend dozens of levels to acquire another weapon art that you're never gonna use anyway because it's hardly worth it at all. But hey, at least you'll get an achievement soon™. Go for it, skeleton, and onward to heightening your technique!

[Cat]

Also you can jump down the hole in the next room, grapple the support beam, and let the chained ogre (if you haven't killed it), kill the two ministry enemies for more exp. Seems to be the easiest exp farm in the game.

[pwnit]

This was posted two years ago, a couple weeks after the game's release. At this point, I don't even remember what are you talking about :P

[xtrux]

have you tried ashina outskirts stairway after defeating divine dragon?

[Doctor-_-Shade]

Hinata Audience chamber after you get the Fathers bell charm has a black robed monk you can easily stealth kill after breaking the wooken/paper wall. 3520 xp per kill on ng+

[hixd]

esta difícil conseguir ese logro

[profilejc98]

I'm in ng+5 and still need a good 10ish levels, I wish bosses awarded much more XP in ng, even with on hard (no charm) it's generally less than an XP level. This is a good strat for grinding it out though

[MAGJr]

I found this one too. It's far easier than using homeward idol and going through a load screen, it's super safe and easy, you don't have to run from enemy to enemy, and this is the highest xp you can get from simply stealth killing one enemy. So there's no time wasted killing lesser enemies and risk of losing stealth is as low as it could be.

[Frotting Christ]

If you're close enough in NG+, I'd recommend grinding out all of the levels you need but don't spend them, then make a copy of your save. Then spend them to get the achievement, then reload the save, and use them all with the dragon mask to level up your AP.