Pointing Pairs and Pointing Triples

Recognize the alignment

Choose a box and one missing digit. Locate every cell in the box that can still contain that digit. If the candidates occupy two cells in the same row, you have a pointing pair; three aligned cells form a pointing triple. The number of candidates matters less than their confinement to one shared row or column.

Suppose digit 4 can appear in only R2C1 and R2C3 within the upper-left box. One of those cells must eventually be 4. Because row 2 can contain only one 4, every candidate 4 in row 2 outside that box can be removed.

Make only the justified eliminations

The pattern eliminates candidates along the aligned line outside the source box. It does not tell you which aligned cell receives the digit, and it does not remove other candidates from those cells. If the candidates are spread across two rows or two columns inside the box, no pointing elimination is available.

Search systematically

After singles stop producing progress, scan each box digit by digit. Candidate highlighting can help, but the proof should remain visible without relying on color alone. Trace the source box boundary, identify the shared row or column, and then inspect only the cells beyond that boundary. The strongest result is often not the elimination itself but the naked or hidden single it creates.

1. Select a box and a digit missing from it.
2. Find every legal candidate for that digit inside the box.
3. Confirm all candidates share one row or one column.
4. Remove that digit from the rest of the shared line outside the box.
5. Rescan affected cells for singles and pairs.

Relate pointing and claiming

Pointing starts in a box and eliminates along a line. The reverse pattern, often called claiming or box-line reduction, starts in a row or column: if all candidates for a digit in that line fall inside one box, the digit can be removed from other cells in the box. Keeping the direction clear prevents accidental over-elimination.