Miracle Sudoku

Miracle Sudoku. Anti-knight, anti-king, and non-consecutive constraints all apply at once.

How to play

Fill the 9×9 grid so every row, every column, and every 3×3 box contains the digits 1 to 9 with no repeats — the classic Sudoku rule. Miracle Sudoku adds one twist: Anti-knight, anti-king, and non-consecutive constraints all apply at once.

Miracle Sudoku is a standard 9×9 grid carrying three extra rules at the same time: anti-knight, anti-king and non-consecutive. Those constraints bind the cells so tightly that a single digit ripples outward and pins its neighbours, which is why the celebrated original miracle sudoku — popularised by Cracking the Cryptic — is solved from just two given numbers.

How to solve Miracle Sudoku

Solve by placement cascade rather than by classic scanning. Take any given digit and rule it out of three zones at once: the eight cells a king could reach, every cell a knight's L-move away, and — via the non-consecutive rule — the four orthogonal neighbours, which can hold neither that digit plus one nor minus one (so next to a 5 you can write neither 4 nor 6). Each fresh placement is usually forced by these three bans acting together, so you chain from cell to cell without ever needing X-wings or colouring. As the grid fills you'll notice the digits settle into repeating diagonal stripes — the same number recurring roughly three cells apart down a diagonal — and spotting that pattern lets you fill whole runs at a stroke. When a cell stalls, look one knight's-move and one king-step out from your most recent digits rather than re-scanning the box.

Every Miracle Sudoku puzzle is free to play in your browser — no ads, no sign-up, and it works offline.

Frequently asked questions

What is Miracle Sudoku?

Miracle Sudoku is ordinary 9×9 Sudoku with three additional constraints applied simultaneously: anti-knight, anti-king and non-consecutive. The name comes from the original puzzle by Mitchell Lee, made famous by Cracking the Cryptic, which contains only two given digits yet has a single solution because the layered rules force every other cell.

What do the anti-knight, anti-king and non-consecutive rules mean?

Anti-knight means no two cells a chess knight's move apart may share a digit. Anti-king means a digit cannot repeat in any of the eight cells touching it, including diagonally (the king's moves). Non-consecutive means two orthogonally adjacent cells cannot hold consecutive numbers, so side-by-side neighbours must differ by at least 2. All three apply on top of the usual row, column and box rules.

How can a Miracle Sudoku have only two given digits?

Because the three extra constraints overlap so heavily that one placement dictates the next. A single digit is banned from its king-neighbours, its knight-cells and — as plus or minus one — its orthogonal neighbours, which usually leaves each surrounding cell just one legal option. The solution therefore cascades outward from the two clues, so no guessing or advanced technique is required.