Where the advanced techniques start
An expert grid is one whose solving path costs more than a hard grid's: fewer clues, more moves, and harder ones. About two in three need locked candidates. A smaller share need a pair, and roughly one in twelve needs a pattern that spans several units — an X-Wing, an XY-Wing, or very occasionally a Swordfish.
Full pencil marks are worth it here
On easier grids, marking every cell wastes time. On an expert grid it is the only reliable way to see the patterns, because every one of them is defined by where a candidate can and cannot go across the whole board.
Enter your candidates with the notes button, keep them current as you place digits, and then look for structure: a digit that appears exactly twice in each of two rows, two cells that share a pair, a cell with only two candidates that sees two others.
Being stuck is part of it
There is no shame in a hint on an expert grid. The hint names the technique and explains the elimination in one sentence, then links to the guide for it. Reading why a move works while you are looking at the position it applies to is how these patterns stop being abstract.
Every expert puzzle here is still solvable by logic. If you cannot find the move, it exists — the generator would have thrown the grid away otherwise.
What these puzzles actually need
We generated 300 puzzles at this level with the same code that builds the board above, solved each one along its logical path, and counted. A technique counts if the path uses it at least once.
| Measured across the sample | Expert |
|---|---|
| Starting numbers, fewest to most | 22–34 |
| Starting numbers, average | 25 |
| Moves to solve, average | 56 |
| Solved by naked singles alone | 0% |
| Need a hidden single | 100% |
| Need locked candidates | 69% |
| Need a naked or hidden pair or triple | 5% |
| Need an X-Wing, XY-Wing or Swordfish | 8% |
The sample uses fixed seeds and is measured again whenever the generator changes, so these figures describe the puzzles this page actually serves.
Common questions
What makes a Sudoku expert level?
A solving path that costs more than any hard grid's: fewer clues, more moves, and usually at least one locked-candidate move. Roughly one expert grid in twelve also needs an X-Wing, XY-Wing or Swordfish.
How many clues does an expert puzzle have?
Usually 22 to 28, though the count matters less than the moves required.
Do expert puzzles require guessing?
No. Grids that cannot be solved with the site's technique list are discarded during generation, so a complete logical path always exists.
Which technique should I learn first?
Locked candidates first — most expert grids here need them. After that the XY-Wing, which is the advanced pattern our expert grids call for most often.