Firework

What Is the Firework Technique?

The Firework exploits a pattern where a digit has exactly two candidate positions in both the row and the column of a single pivot cell. The pivot sits at the intersection, with one wing along the row and one along the column. The digit must appear in at least one of these three cells.

The Firework Pattern in Detail

Pivot P at the intersection. Row wing W1 (the other candidate in the row). Column wing W2 (the other candidate in the column). Both links are strong links. Two strong links share a common endpoint at the pivot.

How the Firework Logic Works

Case 1: Pivot has the digit -- placed at P. Case 2: Pivot does not -- both W1 and W2 must have the digit. Either way, at least one of {P, W1, W2} contains the digit. Eliminate from cells seeing the pivot and at least one wing.

How to Find Firework Patterns

For each digit, find cells where both the row count and column count equal exactly 2 (including the cell itself). That cell is the pivot. The other cells in the row and column are the wings. Look for a cross-hair or plus-sign shape in the pencilmarks.

Why the Firework Technique Is Rare

Requires exactly two candidates in both a row and column with one cell in common, plus an elimination target. Each condition narrows possibilities considerably.

Difficulty Rating and Context

Level 8 (Expert). Harder than basic wings and unique rectangles because the intersection pattern is less obvious. Simpler than chains because it involves only three cells. Related to Two-String Kite and Empty Rectangle conceptually.

Summary

The Firework is a row-column intersection pattern. A pivot forms strong links with two wings. Any candidate seeing the pivot and at least one wing is eliminated. Level 8 (Expert), rare but clean.