SudokuguroWhat Sudoku technique should I learn first?
Learn direct solves first. Scan rows, columns, and boxes for forced placements, then add candidates when direct scanning stops.
Solving Guide
Sudoku Techniques
Learn a practical Sudoku technique ladder from direct solves and candidates to locked candidates, naked and hidden sets, X-Wing, Swordfish, coloring, and uniqueness checks.
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Key Takeaways
- Most Sudoku progress follows a ladder: direct solves, candidates, singles, locked candidates, sets, fish patterns, and linked-candidate logic.
- Candidate discipline matters more than speed because every later technique depends on accurate possible numbers.
- A unique-solution puzzle should reward logical eliminations instead of forcing random guessing.
What are candidates in Sudoku?
Candidates are the numbers that can still fit in an empty cell after checking the cell's row, column, and 3x3 box.
Stage 1: Direct Solves
Begin by scanning one number at a time across rows, columns, and boxes.
Direct solves come from visible constraints and reduce the board enough to reveal later techniques.
Stage 2: Candidate Notes
When direct solves slow down, list possible numbers for selected cells and update them after every confirmed placement.
Focus first on crowded rows, columns, and boxes so your notes stay useful.
Stage 3: Sets, Fish, and Coloring
Naked and hidden sets remove candidates by comparing groups of cells within a unit.
X-Wing, Swordfish, and coloring are worth checking after singles, locked candidates, and sets are exhausted.