So i've been exploring all the ninja-related stuff and there's actually quite a bit to find. The kano paintings are probably your best bet to start with, since there's 10 of them hidden around different castles like osaka and himeji. They're pretty cool once you track them all down and honestly, the art collector quest makes it worth the effort.

The really interesting stuff is scattered throughout iga province, where you'll come across these amazing cultural discovery entries. There's like 125 of them and they tell you all kinds of neat historical facts about the ninja. I found a bunch just by poking around the old training grounds and homesteads, but dont forget to check out the shrines and castles too.

If youre into exploration, keep an eye out for those hidden trails that naoe can use. Look for shuriken marks on trees and these cool rope dart spots above the forests. Sometimes i've noticed certain things only show up during specific moon phases, which is a nice touch.

Your shadow sense is gonna be your best friend here, trust me. It highlights all the important stuff you can interact with. If you're really trying to get everything, the iga area has like 4 castles and 6 legendary chests that are worth checking out, and over in yamashiro you'll find a bunch of temples and shrines with some good discoveries. The kofun tombs are pretty neat too, usually hiding some sweet shinobi gear if you look hard enough.