Casegrid
Magic Square
Fill the gaps so every row, column and diagonal adds up to the same number.
Controls — Tap a cell and type a number. No keyboard shortcuts needed.
How to play
- Each square hides a few cells. Fill them so every row, column and both diagonals share one sum.
- The target is shown: 15 for 3 × 3, 34 for 4 × 4.
- Cells turn red when a line can no longer reach the target — that is your signal to back up.
Tips
- The centre of a 3 × 3 is always one third of the target: 5.
- Pairs opposite the centre add up to one more than the side length squared — 10 in a 3 × 3.
- In a 4 × 4, the four corners and the four centre cells also sum to 34. Use that as a check.
About this game
Magic squares are old enough to appear in Chinese and Islamic art long before they were called puzzles. The 3 × 3 is unique up to rotation and reflection; the 4 × 4 has 880 essentially different solutions.
This version builds both sizes from scratch — the Siamese method for odd squares, complement pairs for multiples of four — then hides a few cells and lets you finish it.
No download, no account, no tracking, no ads.
FAQ
Can a number repeat?
No. Each number from 1 to the square of the size is used exactly once.
Why no 6 × 6?
Singly even squares need a third construction (the LUX method). It is a different puzzle, not a bigger one.
What does Reveal do?
Fills the whole square. It is there to check your reasoning, not to score.
