Chess Basics, No Experience Needed
You do not need to know chess to play CoreSquares. It is a spatial puzzle that happens to borrow how chess pieces move. Here is all the chess you will ever need, in plain language. If you have played before, this will take ten seconds; if you have not, it is genuinely the whole thing.
The one rule
Every piece lights the square it sits on, plus the squares it could move to or attack. Place pieces so their combined coverage lights every target. That is it. There is no capturing, no turns, no opponent.
How each piece moves
Rook
Moves in straight lines, along its row and its column, as far as nothing is in the way. In CoreSquares it lights that whole row and column until a wall, a blocker, or another piece stops the beam.
Bishop
Moves diagonally, as far as the path is clear. It lights both diagonals out from its square, so it covers the squares a rook never can.
Queen
The rook and bishop combined: straight lines and diagonals, all eight directions. The most powerful piece, and the one to save for last.
Knight
Jumps in an L: two squares one way, then one square at a right angle. It is the only piece that leaps over anything in between, and it reaches up to eight squares around it.
King
Steps one square in any direction, so it lights the ring of squares immediately around it. Short range, but precise.
Pawn
The most limited piece. In CoreSquares it lights the two squares diagonally in front of it (up the board), and nothing else. That makes its correct spot easy to spot.
That is the whole game
Once you can picture each piece's reach, every level is just fitting those shapes together until the board is lit. The School world introduces the pieces one at a time so you learn them by feel, and the strategy guide shows you how to combine them.