Nishio

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Nishio

What It Is

Nishio assumes a specific cell-digit, follows the consequences, and if a contradiction appears, eliminates that digit from that cell. It’s a targeted, logical guess-and-check for one candidate.

When to Use

Late-stage puzzles when only a few ambiguous spots remain or a digit is narrowly placed but not provable otherwise.

How to Apply (Step-by-Step)

  1. Pick a candidate digit in a target cell.
  2. Assume the cell equals that digit.
  3. Solve forward with that assumption using normal logic.
  4. If contradiction arises, the digit is false; eliminate it.
  5. If no contradiction, consider the alternative or proceed as needed.

Assume cell R3C6 is 3; if that creates an impossible state, remove 3 from R3C6 and place the remaining option confidently.

See also

Scanning / Cross-Hatching Single Candidate (Naked Single) Single Position (Hidden Single) Naked Pairs / Triples / Quads Hidden Pairs / Triples / Quads Pointing Pairs / Triples (Locked Candidates Type 1) Box–Line Reduction (Locked Candidates Type 2) X-Wing Swordfish Jellyfish XY-Wing XYZ-Wing W-Wing Alternating Inference Chains (AICs) Forcing Chains / Forcing Nets Nishio Coloring Multi-Coloring Uniqueness Techniques (Unique Rectangle etc.) Fish Variants (Finned X-Wing, Sashimi etc.) ALS Techniques (ALS-XZ, ALS Chains) Sue de Coq Pattern Overlay / Template Method
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