Pointing Pairs

Volodymyr Sakhan  ·  April 23, 2026

Pointing Pairs is one of the most powerful intermediate sudoku techniques. Once basic singles are exhausted, a Pointing Pair lets you eliminate candidates from an entire row or column in a single step — often unlocking a chain of further deductions. Also known as Locked Candidates Type 1, it bridges the gap between beginner strategies and more advanced subset methods.

To use this technique you need pencil marks (candidate digits written in empty cells). If you haven't tried pencil marks yet, read that guide first — then come back here.

What Is a Pointing Pair?

A Pointing Pair occurs when a candidate digit appears in exactly two cells within a 3×3 box, and both those cells lie in the same row or column. Because one of those two cells must contain that digit (to satisfy the box), and both are on the same line, that digit is guaranteed to occupy that line inside the box — so it cannot exist anywhere else on that line outside the box.

The same logic applies to Pointing Triples: three aligned cells in a box that all carry the same candidate. Triples are rarer but work identically. The complementary technique — a candidate confined to one box within a row or column — is Box/Line Reduction (Locked Candidates Type 2), covered in its own article.

When to Use Pointing Pairs

Reach for Pointing Pairs after basic singles (Naked Singles and Hidden Singles) no longer make progress. In intermediate puzzles, this is usually the very next step once your pencil marks are fully written in — often used alongside Naked Pairs.

• You have filled in all naked and hidden singles — no empty cell has only one candidate, and no digit is confined to one cell in a house.
• Pencil marks are complete: every empty cell shows all the digits that could legally go there.
• The technique is most effective when the shared row or column has several empty cells outside the box — more cells means more eliminations per step.

Step-by-Step Example

The following three diagrams use two real puzzle positions to show Pointing Pairs in action — once along a column, once along a row, and once pointing upward from a bottom box.

Example 1 — Digit 3 Pointing Down Column E (Box 2)

In box 2 (top-center, columns D–F, rows 1–3), digit 3 can only go in two cells: E2 and E3. Both are in column E.

1. Write pencil marks for all empty cells in box 2 (columns D–F, rows 1–3).
2. Find every cell in the box that can hold digit 3. Only E2 {1,3,5,9} and E3 {1,3,5,9} qualify — digit 3 is blocked from all other cells in the box by existing clues.
3. Both cells are in column E — digit 3 is "pointing" down column E from this box.
4. Conclusion: wherever digit 3 lands in box 2, it will be in column E. So digit 3 cannot appear in column E anywhere outside box 2.
5. Scan column E below the box: E5 = {1,3,5}, E7 = {1,2,3,8}, E9 = {1,2,3}. All three carry candidate 3.
6. Eliminate 3 from E5, E7, and E9.
7. After elimination: E5 = {1,5}, E7 = {1,2,8}, E9 = {1,2}. E9 is now down to two candidates and may unlock further techniques immediately.

When a candidate is trapped in one column within a box, it clears from the rest of that column — no matter where else the digit might seem to fit.

Example 2 — Digit 6 Pointing Along Row 1 (Box 2)

Still in box 2, same grid — but now look at digit 6. It can only go in D1 {1,6} or F1 {1,5,6} within the box. Both cells are in row 1.

1. Check which cells in box 2 can hold digit 6. Digit 6 is already placed elsewhere in its rows and columns, leaving only D1 and F1.
2. Both cells are in row 1 — digit 6 points along row 1 from this box.
3. Therefore digit 6 cannot appear in row 1 outside columns D–F.
4. Scan row 1 to the left of the box: A1 carries candidate 6 — eliminate it.
5. C1 also carries candidate 6 — eliminate it.
6. A1 and C1 lose 6 from their pencil marks. Continue scanning for further techniques.

The same box can yield multiple pointing pairs — here box 2 delivers both a column-pointing pair (digit 3) and a row-pointing pair (digit 6).

Example 3 — Digit 4 Pointing Up Column C (Box 7)

In a second puzzle, box 7 (bottom-left, columns A–C, rows 7–9): digit 4 can only go in C7 {3,4,5,9} or C9 {4,5,7}. Both are in column C.

1. Write pencil marks for box 7 (columns A–C, rows 7–9).
2. Digit 4 appears as a candidate only in C7 and C9 — both are in column C.
3. One of C7 or C9 must hold digit 4 to satisfy box 7; either way, it lands in column C.
4. Eliminate 4 from all other empty cells in column C outside rows 7–9.
5. C4 = {4,5,6,7} → {5,6,7}. C5 = {3,4,5,7,9} → {3,5,7,9}.
6. C4 is narrowed but not yet solved; continue scanning the puzzle for further techniques.

Pointing pairs work identically whether the pair points up, down, left, or right — the direction just determines which part of the line is cleared.

How to Spot Pointing Pairs

With complete pencil marks, scan each box systematically: for every unsolved digit, collect the cells in that box where the digit is a candidate. If all those cells share the same row or column and there are 2 or 3 of them, you have a Pointing Pair or Triple.

• Go box by box (all 9), digit by digit (1–9). It sounds slow but each check takes only a second once you're practiced.
• Pointing Triples follow the same logic with three aligned cells — rarer but equally powerful when they appear.
• Typical trigger: after filling in all singles, the remaining candidate layout often exposes pointing pairs immediately.
• The related technique Box/Line Reduction (Locked Candidates Type 2) works in the opposite direction: a candidate confined to one box within a row or column lets you eliminate it from the rest of that box.

Our full solving guide lists every technique in order of difficulty — use it as a reference when you get stuck.

Practice Pointing Pairs Online

Pointing Pairs appear regularly in medium sudoku. Once you recognize the pattern, you'll spot it in every intermediate puzzle you play.

After mastering Pointing Pairs, try Naked Pairs if you haven't already — together these two techniques cover the majority of intermediate-level eliminations.

Frequently Asked Questions