Technique

Claiming Pairs

The mirror of pointing pairs: when a digit inside one row or column only fits inside a single box, it can be crossed off the rest of that box - the line 'claims' the digit for that box.

💡 What It Is

A line-to-box elimination. If every remaining candidate cell for a digit within one row or column falls inside a single box, the digit is locked into that box as far as the line is concerned.

🔍 How To Spot It

Pick a row or column and a digit. List every empty cell in the line that could still hold it. If they all sit inside one box, you have a claiming pair (or triple).

✅ Why It Works

The digit has to go somewhere in the line, and every legal spot for it sits inside the same box - so the rest of that box can't be it.

📝 Worked Example

In row 5, the digit 7 is only a candidate at R5C4 and R5C6 - both in box 5. Since 7 must land somewhere in row 5 and both its spots are in box 5, eliminate 7 from the rest of box 5.

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