Windoku · Hard

Naked Pair in Windoku

Two cells in a house that hold the same two candidates. Those two digits are theirs.

The idea

When two cells in a house hold only the same two candidates, no other cell in the house can use those two digits.

In Windoku the pair can sit in a window, and then those digits are eliminated from the whole window.

Worked examples

2 positions from real Windoku puzzles on this site, the familiar case first. Step through each one: the board lights what each step talks about, and the arrows show what rules what out.

A pair in a row

Hard puzzle · Naked Pair

In row 2, look for two cells that hold the same two candidates between them.

Step 1 of 4Step 2 of 4Step 3 of 4Step 4 of 4

A pair in a window

Hard puzzle · Naked Pair

Both cells of the pair are in the lit window, so the window is cleared too.

Step 1 of 5Step 2 of 5Step 3 of 5Step 4 of 5Step 5 of 5

Where it fits

HardNaked Pair is a Hard technique: Hard Windoku puzzles are the first to need it.

The Classic Naked Pair lesson teaches it on a plain 9×9 board. The Windoku overview explains the rule and the levels.

Naked Pair in the other styles: Sudoku X, Jigsaw, Thermo, Arrow, Kropki.

Try it on a Hard Windoku puzzle. Next Step points it out when it is the move.

The worked examples, every step

A pair in a row

Hard Windoku puzzle · Naked Pair

  1. In row 2, look for two cells that hold the same two candidates between them.
  2. R2C3, R2C5 hold only {1, 6}. Those two digits must fill those two cells, so no other cell in row 2 can use them. The arrows point to the cells that lose them.
  3. Eliminate {1, 6} from R2C1, R2C6.
  4. Done: 6 is eliminated from R2C1, R2C6.

A pair in a window

Hard Windoku puzzle · Naked Pair

  1. Both cells of the pair are in the lit window, so the window is cleared too.
  2. In the bottom-right window, look for two cells that hold the same two candidates between them.
  3. R7C8, R8C6 hold only {6, 8}. Those two digits must fill those two cells, so no other cell in the bottom-right window can use them. Nor can a cell that sees both of them: R7C4 sees R7C8 in row 7 and R8C6 in box 8. The arrows point to the cells that lose them.
  4. Eliminate {6, 8} from R7C4.
  5. Done: 8 is eliminated from R7C4.

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