Expert Sukaku
The ultimate test. Expert Sukaku puzzles push the variant constraint to its limit, requiring flawless logic and the most advanced solving techniques. Only the sharpest minds complete these.
What to expect at Expert level
Expert Sukaku puzzles are constructed to be as difficult as possible while remaining logically unique. Every cell placement flows from precise reasoning - Guessing never helps. The constraint creates complex cross-cell dependencies that demand full concentration.
Designed for solvers who have mastered Hard and are looking for the definitive Sukaku experience.
Difficulty overview
About Sukaku
Sukaku (数角) is a Sudoku variant where instead of given digits, each cell is given a set of possible candidates. The solver must eliminate candidates using standard Sudoku logic until each cell has exactly one remaining candidate. Some Sukaku puzzles provide very sparse candidate sets (near-complete givens), while others provide full or nearly-full candidate lists, requiring advanced techniques to solve.
Solving Techniques for Expert Level
| Technique | Description | Level |
|---|---|---|
| Candidate Scanning | Start by scanning rows, columns, and boxes — any candidate appearing in only one cell in a group must be placed there. | Beginner |
| Cross-Hatch Elimination | When a digit is placed (or reduced to one candidate), eliminate it from all cells in the same row, column, and box. | Beginner |
| Naked Singles | A cell with only one remaining candidate is a naked single — the digit is forced. In Sukaku, this happens automatically when you eliminate down to one candidate. | Intermediate |
| Hidden Singles | A candidate that appears exactly once in a row, column, or box must be placed in that cell regardless of how many other candidates that cell shows. | Intermediate |
| Pair Elimination | Two cells in a group that share only the same two candidates form a naked pair — both candidates can be eliminated from all other cells in that group. | Advanced |