One of Hogwarts Legacy's nicest surprises is that there always seems to be another puzzle around the corner. That goes for the most plentiful challenges in Hogwarts and its surroundings, like Merlin Trials and Daedalian Keys, but also for the bonus puzzle rooms hiding in plain sight across the highlands.
Of these special challenges, the most inventive I've found so far are two caves housing a pair of puzzles that ask for a little bit of chess know-how to figure out. Solving both of them also requires a late-game spell and high level lockpicking skills, so don't bother going after these if you're still early in Hogwarts Legacy (though mods to get around those hurdles are always an option on PC).
Here's where to find and how to solve Hogwarts Legacy's chess puzzles.
The first chess puzzle is waiting inside a dusty cave on the northwestern edge of Poidsear Coast, the first chunk of the southern half of the map. The area is rated for levels 20-40, so you won't have an easy time around here until you're at least halfway through the game. The cave sits near a particularly nasty spider den that you'll probably want to deal with before entering, but it's also possible to slip by with a handy invisibility spell.
To open the cave:
Spin the two windmills outside the cave entrance by rapidly casting Depluso on each until the entrance barriers retract. If you fully spin both, the entrance will stay unlocked. Continue down the stairs, past piles of pots and other rubbish until you reach a giant chessboard.
To solve the puzzle:
Cast Revelio and find an object in the room that looks mysteriously like a chess piece, and then cast Transformation on it, turning it into that chess piece. For me it was a pot with a cubic rim like a rook, but it could be different for you (apparently it can even be a chair). You're trying to "checkmate" the black king piece, so place the piece on a square where it could move to take the king. Here's a cheat seat:
If you place your piece correctly, it'll magically knock into the king and crumble it to bits, unlocking the chest behind it. Enjoy a scarf that's probably worse than the one you're wearing.
The only other chess puzzle we're aware of is in the next region over, Marunweem Lake. You'll find it in the middle of the region's central bulge, not far from a hamlet and directly next to a poacher camp. Like in Poidsear, this region is for levels 20-40, so take caution. Dispense of the poachers and find the cave entrance in the cliff face behind it.
To open the cave:
Find a nearby tent with a puzzle cube inside of it, and unlock the cage with Alohomora. You'll need level three Alhomora for the job, which requires gathering all of the Demiguise statues. If you, like me, enjoy solving puzzles but not hunting down statues, this PC mod to unlock all spells can save you some time. Levitate the cube to the pedestal in front of the cave entrance and then cast Glacius on the cube.
To solve the puzzle:
This one will have an identical solution to the first, but likely with a different chess piece. Cast Revelio to find the object that looks like a chess piece and cast Transformation on it. This time for me, it was a pot with an oblong tip like a bishop. Then levitate the chess piece to a space where that piece could take the black king piece. Here's that cheat sheet again:
If you're right, the king piece will fall and you've got yourself another scarf for the collection.
