Firework

Level 6 · Orange Belt (Green Stripe)

Strategy:

Firework

Requires:

X-Wing

Overview

Firework uses a pivot cell at the intersection of a row and column, where a digit has strong links along both the row and column. The pattern forces the digit into specific cells, allowing eliminations elsewhere.

How It Works

  1. Find a pivot cell at the intersection of a row and column.
  2. The digit must form a conjugate pair in the row (pivot + one cell) and column (pivot + one cell).
  3. The digit must be in the pivot or in both endpoint cells.
  4. Eliminate the digit from cells seeing both non-pivot endpoints.

Example

Look for Firework.

1

Firework

Found a Firework pattern. Pivot r5c1 at the intersection of Row 5 and Column 1 connects to r5c6 and r4c1.

2

Firework

Digit 5 in Row 5 is confined to r5c1 and r5c6. Digit 5 in Column 1 is confined to r5c1 and r4c1.

3

Firework

Either r5c1 = 5, or both r5c6 and r4c1 contain 5.

4

Firework

These highlighted candidates are seen by the firework pattern and cannot keep 5: r4c2.

5

Firework

Eliminate 5 from r4c2.

6

Result after applying the technique.

Tips & Patterns

  • Firework patterns radiate from a single pivot point along a row and column - hence the name.
  • The pivot is at the center, with 'sparks' along both lines.
  • Look for digits with exactly 2 occurrences in both a row and column sharing a cell.