How to play nonograms

1. A number describes a group, not a position.

A 3 means three filled squares touching in one unbroken group. 3 1 means a group of three, then a separate group of one. Keep the groups in that order, with at least one empty square between them.

Read a row’s clues from left to right. Read a column’s clues from top to bottom. The numbers do not tell you how many empty squares come before the first group or after the last.

2. Empty and unknown are different.

A blank square means “I have not decided.” An X means “I have proved this is empty.” Use Mark for X. Empty squares are useful evidence for the lines crossing them.

The ? in this guide means unknown; it is not an extra tool in the game.

3. Take the moves with only one answer.

A clue of 0 makes the whole line empty. A single clue equal to the line’s length fills the whole line. Check both rows and columns for these easy starts.

4. Finish a line, then look across it.

If a line has only the clue 1 and one square is already filled, the rest must be X. That one square uses the entire clue.

Repeat this loop: prove a square → check its crossing line → mark any new certainties. A row does not need to be finished before you move to a column.

5. Check the groups, not just the total.

For a clue of 2 1, three filled squares in one group are wrong: they read as 3. The lengths, order and separating gaps must all match, in every row and column.

Do not fill a square because it would make the picture look right. A correct move must follow from the clues.

Using this board

Click Start to begin. Choose Fill, Mark or Erase, then tap or drag along a row or column. Switching tools also applies that tool to the selected square. Undo reverses one stroke.

Auto-mark X is on by default: it marks zero lines at the start and adds empty marks around completed lines. You can turn it off in Settings. The guided lessons keep these marks manual so you can practise the reasoning.

1. Count the space the clues need.

Add the group lengths and one separator for each pair of groups. For 2 2, that is 2 + 1 + 2 = 5. In five squares, everything is fixed.

If space remains, the groups can slide. That does not make the line useless: some squares may still be certain.

2. Find the overlap.

Take one group of 5 in a seven-square line. Place it as far left as possible, then as far right as possible. Squares 3, 4 and 5 are covered either way, so they must be filled.

These two extremes prove the middle because there is a single continuous group: sliding it between the extremes cannot uncover those squares.

3. Let an edge fix the direction.

A line has only the clue 3, and its first square is filled. The group cannot grow outside the board, so it must occupy squares 1–3. All the remaining squares are empty.

4. Join a group—or keep two groups apart.

With only the clue 3, filled squares at positions 2 and 4 must belong to that one group. Fill the bridge at position 3. The group is complete, so mark the rest X.

With clues 2 2, a filled pair at positions 2–3 is already the first group. Put an X on either side so it cannot grow. Leave the second group for another deduction.

5. Use X to shrink the problem.

A line has only the clue 3. An X at square 3 leaves two spaces before it—too few for that group. Those two squares must also be X. The group has to be somewhere on the other side.

Now suppose X marks leave only squares 4–7 available. A group of 3 can occupy 4–6 or 5–7. In both cases, squares 5 and 6 are filled. It is the same overlap idea, inside a smaller space.

6. If you are stuck, make the next question smaller.

1. Check changed lines. Revisit the rows and columns touched by your last marks.
2. Look for missing X marks. Has a completed group been separated? Is a whole line already satisfied?
3. Check your assumptions. Is that group definitely tied to that clue? Does every legal placement agree?
4. Review the earliest uncertain move. A contradiction can come from an earlier mistake; adding another guess makes it harder to trace.

The current puzzles have been checked to solve using row-and-column logic from an empty board. You do not need to guess or recognise the picture to finish them.

One habit to keep: before every mark, ask “Could this square be different in another legal arrangement?” If yes, leave it unknown for now.

In Free Play, each puzzle reveals a complete picture. In Mosaics, each puzzle reveals one piece of a larger picture. Find your earned pictures and pieces in Collection.