Pointing Pairs/Triples

Intermediate

When a digit in a box is confined to one row or column, it can be eliminated from that row or column outside the box.

How It Works

When a digit in a box can only appear in cells that all share the same row or column, that digit can be eliminated from all other cells in that row or column outside the box.

This uses the box-line interaction: since the digit must be in that row/column within the box, it cannot be in that row/column outside the box.

Example

36
9
26
368
2
167
5
46
3
853
147
479
179
24
124
126
472
159
158
158
38
138
168
259
126
159
478
378
348
136
135
57
269
126
1569
578
578
358
136
135
47
259
126
159
47
478
348
138
135
57
125
126
158
238
148
248
79
357
48
125
126
158
238
148
24
79
357
48
259
26
589
348
348
348
136
15
57
Key cells of the techniqueCells where elimination is appliedCandidate to be placedEliminated candidate (crossed out)

In Box 1, digit 5 is only a candidate at R1C1 and R1C3 (both in Row 1) → Eliminate 5 from R1C4 through R1C9.

Practice with a Real Puzzle

This 9×9 puzzle is solver-verified to require this technique on its solution path.

Easy32 givensStrict