Difficulty

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Description

This is a Y-Wing.

• The cell is called pivot cell.
• The cells are called wings. Both must see the pivot cell.

All three cells (pivot + 2 wings) must each have exactly two candidates.

One of those candidates must be in both wings, but not in the pivot cell. Here the common candidate is the 3.

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For this example, there are two possible outcomes:

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Since there must be a 3 in one of those two cells, we know that all cells that see those two cells cannot hold a 3.

The cells are seen by both wings, so we can eliminate the common candidate (3) from them.

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Another way to look at it

If any of the 3 were true...

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... then that would leave only one candidate in each wing...

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... and the pivot cell would have no candidates left, and therefore no solution.

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Spread over four boxes

In case the pivot cell is not in the same box as a wing, the Y-Wing spreads over four boxes.

In this case, there is only one cell that both wings see. ()

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Y-Wing Examples

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