Expert sudoku: X-wings, Y-wings and swordfish

Expert sudoku grids with 24 to 27 clues, each with a single solution that needs at least one X-wing, Y-wing or swordfish. The hint shows the pattern on the board, so this is a good place to learn them. No app, no sign-up, no interstitial before play; works offline and with the keyboard.

How to play expert sudoku

1. The rules do not change: 1 to 9 once in each row, column and 3×3 box.
2. Expert grids start with 24 to 27 givens and need every Hard technique as well.
3. Work with full notes. Fill notes writes them in one press.
4. Clear everything the singles, pairs and pointing techniques allow before hunting for a wing.
5. Hint shows the elimination pattern first, then the placement it leads to, named by the hardest technique used.

Expert sudoku: what techniques you need

Expert grids are rated as needing at least one of three patterns that link cells across the board rather than inside one unit.

X-wing

Pick a digit and find two rows where it has exactly two candidate cells, and those cells sit in the same two columns. The digit must occupy one diagonal of that rectangle, so it goes in each of those columns within those two rows. Remove it from the rest of both columns. The same works with columns and rows swapped.

Swordfish

The three-row version of the X-wing. Three rows each have two or three candidates for a digit, all within the same three columns. Remove the digit from those columns everywhere else. Look for it when a digit has few candidates left across the grid.

Y-wing

Find a pivot cell with two candidates, say 4 and 7, that sees two other two-candidate cells: one with 4 and 2, one with 7 and 2. Whichever digit the pivot takes, one wing becomes 2. Any cell that sees both wings cannot be 2.

Hunting efficiently

For X-wings and swordfish, go digit by digit and note rows or columns where the digit appears only twice. For Y-wings, list cells with exactly two candidates; the pattern needs three of them.

Stats, hints and printables for expert sudoku

The timer starts on your first move and pauses when you switch tabs. Expert stats stay in your browser: played, won, win rate, best and average time. Undo and redo cover the whole game. The first two hints per puzzle are free; later hints may offer a short ad or a 30-second wait. A puzzle code such as A7K3Q (?p= in the address) replays the same grid, and the win panel gives a result to share.

Expert grids also print as PDFs.

Plays anywhere, no app, no account

Expert sudoku pencil marks stay legible on a phone, and hints outline the X-wing or Y-wing cells on the board itself. Tidy Puzzles runs entirely in your browser: there is no app to install, no account to create and no interstitial before you can play. After the first visit the game also works offline, because each puzzle is generated on your device from a seed. Every board can be played with the keyboard alone, on a phone or a desktop, and your stats and unfinished puzzles stay in this browser rather than on a server.