Expert Sudoku Puzzles
Expert Sudoku is built for players who already solve Hard boards comfortably and want puzzles that push back. Boards start with 30 to 32 givens, so the grid does not look much emptier than Hard, but every Expert puzzle is generated so that hidden singles are required throughout and the occasional locked-candidate elimination is needed. The obvious moves run out early. From then on, the board only moves when you make it move.
The Expert difference
At Hard, a diligent scan will usually turn up a cell with one possibility. At Expert, long stretches have none. Progress comes from the other direction: pick a digit, pick a unit, and prove that the digit has exactly one cell left. Doing that reliably means keeping complete, accurate notes for the emptiest regions of the grid and updating them after every placement.
Expert Sudoku techniques
- Hidden singles in rows, columns and boxes, found by checking where each digit's candidates remain.
- Pointing pairs and triples. When a digit's candidates in a box line up on one row or column, remove the digit from the rest of that line.
- Box/line reduction. The reverse: if a digit's candidates in a row all fall inside one box, clear the digit from the rest of that box.
- Naked pairs. Two cells in a unit sharing the same two candidates lock those digits out of the unit's other cells.
Expert Sudoku strategy, step by step
- Scan for any free placements and take them; there are usually a handful at the start.
- Switch on notes and fill candidates for every empty cell in the three emptiest boxes.
- Walk digit by digit through those boxes looking for hidden singles and pointing pairs.
- Extend the notes to the rest of the grid as the middle game begins. Keep them tidy: erase candidates the moment they are ruled out.
- When a placement completes a unit, re-check every digit that unit now excludes.
Next level
Master Sudoku drops the givens to as few as 23 and makes naked pairs and locked candidates routine. To consolidate first, Hard Sudoku offers the same techniques at a gentler pace. Each technique named above is explained with examples in the techniques guide.
Frequently asked questions
How many givens does an Expert Sudoku have?
30 to 32. The count is similar to Hard; the difference is that Expert boards are selected so that hidden singles are unavoidable and locked candidates sometimes appear.
Can Expert puzzles be solved without notes?
In principle yes, because every step is a single or a locked candidate, but keeping that much information in your head is slow and error-prone. Notes are the practical way to play Expert.
What is the difference between Expert and Master?
Master boards have fewer givens (23 to 28) and regularly require naked pairs and pointing pairs, whereas Expert leans on hidden singles with only occasional eliminations.