Crane

Level 8 · Blue Belt

Strategy:

Single-Digit Patterns

Overview

Crane uses two conjugate pairs of the same digit: one in a box and one in a line. The pairs connect through a shared cell, forming a pattern where one of the two tail cells must contain the digit.

How It Works

  1. Find a digit that forms a conjugate pair (exactly 2 occurrences) in a box.
  2. Find another conjugate pair for the same digit in a row or column.
  3. The pairs must share exactly one cell (the connection point).
  4. Eliminate the digit from cells that see both tail cells (the non-shared endpoints).

Example

Starting position

Look for Crane.

1

Find two conjugate pairs on 2

Find a box and a row or column that each have exactly two cells with candidate 2.

2

Pairs in box 8 and column 7

Box 8 has a conjugate pair, and column 7 has a conjugate pair for digit 2.

3

The pairs connect through row 8

These pairs are connected through row 8, forming a Crane pattern.

4

r9c5 or r9c7 must be 2

Either r9c5 or r9c7 must be 2, so cells seeing both tails cannot keep 2: r9c8.

5

Remove 2 from cells seeing both tails

Remove 2 from the cells that see both r9c5 and r9c7: r9c8.

6

Result

Result after applying the technique.

Tips & Patterns

  • Crane is closely related to Skyscraper and Two-String Kite - all three use two conjugate pairs connected through a shared unit.
  • The elimination targets cells that see both endpoints of the 'crane arms'.
  • Look for digits with exactly 2 occurrences in both a box and a line.