How to Play Nonograms

To play a Nonogram, read the clues beside the rows and columns, fill cells that must belong to clue blocks, and mark cells that are proven empty. Each new mark gives you more information in the crossing direction. Keep alternating between rows and columns until every clue is satisfied.

You do not need to identify the hidden picture in advance. The picture appears as a consequence of solving the clues.

Before your first move

Make sure you can distinguish three cell states:

• ■ filled — this cell is proven to belong to a clue block;
• × empty — this cell is proven not to be filled;
• ? unknown — you do not yet know the final state.

A digital game may represent those states with different controls, icons, or gestures. The solving logic is independent of the interface.

The important rule is: do not turn an unknown cell into filled or empty until the clues justify it.

Step 1: Read the clues for one promising line

Choose a row or column where the clues strongly restrict the possible placements.

Easy starting points include:

• a block that fills the whole line;
• several blocks whose lengths plus mandatory gaps almost fill the line;
• a long block that must overlap itself wherever it is placed;
• a line with no filled blocks.

For a 5-cell row with clue 5, every cell is immediately filled.

For a 5-cell row with no blocks, every cell is immediately empty.

Most lines are less direct, but these obvious cases create the first information for the crossing lines.

Step 2: Fill only cells that are forced

Suppose a line has 10 cells and clue 7.

The 7-block could start at cell 1, 2, 3, or 4. If you compare the extreme placements, some central cells are filled in every legal position.

Those common cells are forced.

You do not need to decide where the whole block sits yet. Fill only the cells that are guaranteed.

This habit is fundamental: partial certainty is useful.

Step 3: Mark cells that are proven empty

Empty cells are not just cleanup marks. They actively constrain the puzzle.

You can often mark cells empty when:

• a clue block is complete and cannot extend farther;
• all clues in a line have been fully placed;
• a region is too short to contain any remaining block;
• a line has no filled blocks;
• another constraint proves a block cannot reach that cell.

Marking an empty cell splits or narrows the available space for clue blocks and may create the next deduction.

Step 4: Use each result in the crossing direction

Every filled or empty cell belongs to both one row and one column.

If you solve part of a row, immediately reconsider the columns crossing those changed cells.

A filled cell may tell a column that one of its blocks must pass through that position.

An empty cell may cut a column into smaller open segments or eliminate a possible placement.

Then deductions in those columns feed back into rows.

This repeated cross-referencing is the engine of a normal Nonogram solve.

Step 5: Repeat the scan

After every useful deduction:

1. inspect the affected crossing lines;
2. update any completed blocks or impossible spaces;
3. look for newly forced filled cells;
4. mark newly forced empty cells;
5. return to other constrained lines.

You are not expected to solve one row completely before touching the rest of the puzzle.

A row can remain partly unknown for a long time. The information needed to finish it may come from several columns later.

A complete 5×5 beginner example

Consider this small puzzle:

Row clues:

1
1
5
1
1

Column clues:

1  1  5  1  1

Move 1: Solve the full row

The middle row has clue 5 in a 5-cell grid.

It must be:

■■■■■

All five cells in that row are filled.

Move 2: Solve the full column

The middle column also has clue 5.

It must be:

■
■
■
■
■

The center cell was already filled, and the other four cells in that column are now forced filled too.

Move 3: Finish the remaining rows

Each remaining row has clue 1.

Each of those rows already contains one filled cell in the middle column, so that filled cell accounts for the complete clue.

Every other cell in each of those rows must be empty.

Move 4: Check the columns

The outer columns each have clue 1.

Their only filled cell is in the middle row, so those clues are also complete. The final grid satisfies every row and column.

The resulting shape is visible only after the logic has done the work.

How do you know when a clue is complete?

A clue block is complete when you know which consecutive filled cells belong to it and the block has exactly the required length.

For example, if a line has one clue 3 and you have proved three consecutive cells filled as that block, it cannot extend to four cells.

Its neighboring cells, when they exist, must therefore be empty.

With multiple clues, be careful about block identity. Three filled cells do not automatically complete a clue 3 if the current line still allows them to belong to a different unresolved structure.

Should you cross off clue numbers?

You can, if the interface supports it and the block is genuinely resolved.

Crossing off or dimming a completed clue is an organizational aid, not a solving rule. It can reduce visual clutter on larger puzzles.

Do not mark a clue complete merely because you see the right number of adjacent filled cells. First make sure the block's position and identity are actually fixed.

What should you do when no line is obvious?

Do not start guessing.

Instead, scan for lines with the least freedom:

• long blocks;
• clue sequences with a large minimum span;
• lines containing useful confirmed filled cells;
• lines divided by confirmed empty cells;
• lines where a clue can fit into only one remaining segment.

If simple deductions stop producing progress, move to more systematic techniques such as block reach, line segmentation, valid line patterns, or contradiction reasoning.

Common beginner mistakes

Trying to place the entire block too early

You may know that some cells are forced without knowing the exact block start. Mark the certain cells and leave the rest unknown.

Ignoring empty cells

A confirmed empty cell can be as informative as a filled one. Record it.

Staying on one direction too long

Rows and columns are designed to constrain each other. After a useful mark, check the crossing lines.

Guessing from the emerging picture

The picture can be misleading before completion. Use clue logic.

Treating every unfilled cell as empty

Unfilled is not a logical state. A cell is either confirmed empty or still unknown.

A reliable beginner solve loop

Use this sequence until it becomes automatic:

1. scan for highly constrained rows and columns;
2. fill cells that must belong to blocks;
3. mark empty cells that cannot belong to blocks;
4. cross-reference every changed cell;
5. close completed blocks with separators where justified;
6. re-scan the puzzle;
7. move to a deeper technique only when basic line logic stops.

This loop remains useful even on advanced puzzles. Harder techniques usually create new filled or empty cells, after which you return to the same scan-and-propagate process.

FAQ

Do you start with rows or columns?

Either. Start with whichever lines have the strongest constraints. A good puzzle often offers useful moves in both directions.

Should I fill every possible cell in a block?

No. Fill only cells that are guaranteed across all legal placements you are considering.

Are X marks required?

The symbol is not required, but tracking confirmed empty cells is extremely useful. On paper or in an app, use whatever empty-state notation the puzzle provides.

Can I solve one row completely before moving on?

Sometimes, but not usually. Most puzzles require information to pass repeatedly between rows and columns.

What if I make a mistake?

A wrong filled or empty mark can make later clues appear impossible. Recheck the earliest uncertain deductions rather than forcing new placements to fit.

Is guessing part of normal Nonogram play?

For a well-designed logic puzzle, the aim is to make deductions from constraints. If you feel forced to guess, first look for information you have not propagated or a more advanced logical step.

What to learn next

Read How to Solve Nonograms for a structured solving strategy, then learn the core techniques beginning with Exact-Fit Lines and Overlap.