Nonogram Puzzles Free | How to Solve Picross Online

Nonogram puzzles (also called Picross, Griddler, or Hanjie) are grid logic puzzles where you fill in cells based on number clues. Each row and column has a list of numbers telling you how many consecutive filled cells appear — you figure out exactly which cells to fill using logic alone.

If you haven't tried one yet, PlayBrain's Nonogram (Pixel Logic) is completely free in your browser — no download, no account. Start with a 5x5 puzzle to see the solving technique in action before trying larger grids.

---

How to Read Nonogram Clues

Each row and column has a clue: a sequence of numbers separated by spaces.

• "3" means 3 consecutive filled cells somewhere in that line
• "2 4" means a group of 2 cells, then at least one empty, then a group of 4 cells
• "1 1 1" means three separate single cells with gaps between them

The groups must appear in left-to-right (or top-to-bottom) order, with at least one empty cell between groups.

---

Step-by-Step Solving Technique

Step 1: Fill Definite Cells with Block Overlap

The most powerful starting technique: for any line, figure out where the clue groups *must* overlap regardless of position.

If a row is 10 cells wide and the clue is "7", the group of 7 must fill cells 1-7, 2-8, 3-9, or 4-10. Every possibility includes cells 4-7. So cells 4-7 are *definitely* filled — mark them.

The formula: If a group has length L and the available space has length S, the certain fills are in the middle (L - (S - L)) = (2L - S) cells.

Example in a 10-cell row:

• Clue "8" → certain cells: 8 - (10 - 8) = 6 cells in the middle
• Clue "5" → certain cells: 5 - (10 - 5) = 0 cells (too many positions possible)
• Clue "10" → certain cells: all 10 (only one position)

Step 2: Mark Cells That Must Be Empty

When groups are large relative to the space, some cells provably cannot belong to any group:

• The last group can't reach the first cell if space is too short
• Early cells might be out of reach for later groups

When you mark a cell as "definitely empty" (usually shown with an X), it splits the line into segments and often unlocks more deductions.

Step 3: Use Edge Clues Aggressively

If the first clue in a row is 1, the first cell might be filled OR might be the first empty cell. But if the first clue is 1 and there's already a filled cell in position 1, the rest of that clue is done — mark position 2 as empty (the group ends).

More usefully: if you've confirmed that a filled cell IS at the edge, the group must start there. For a clue of "4" starting at cell 1, cells 1-4 are all filled.

Step 4: Cross-Reference Rows and Columns

Every cell is constrained by BOTH its row clue and column clue. Solving rows gives information for columns and vice versa.

After each deduction:

1. Check what the new information tells you about the perpendicular lines
2. Update those lines with the new constraints
3. Repeat until no new deductions are possible

This cross-referencing loop is the heart of nonogram solving. Start with the most-constrained lines (largest clues relative to grid size) and work outward.

Step 5: Eliminate by Process of Elimination

As you mark more empty cells (X marks), the remaining space for each group shrinks. A clue of "3" that had 7 possible positions might have only 2 after some Xs are placed. Apply the overlap technique again with the reduced space.

---

Common Mistakes Beginners Make

Guessing instead of deducing. Every cell in a valid nonogram can be determined by logic alone. If you're guessing, you're missing a deduction somewhere. Go back and look for more constrained lines.

Ignoring the X marks. Marking empty cells is as important as marking filled cells. Empty cells divide lines into segments and unlock new deductions.

Starting with the hardest lines. Counter-intuitive, but start with the most-filled lines (biggest numbers relative to grid width). They give you the most immediate information. Lines with small clues in large spaces should be solved last, when other constraints have narrowed their possibilities.

Forgetting about "at least one empty between groups." The gap between groups is easy to miss. Two groups of "2 3" need at least 2 + 1 + 3 = 6 cells minimum. If a 6-cell row has clue "2 3", both groups are completely determined (exactly one solution).

---

Nonogram Solving Example

Let's solve a 5-cell row with clue "3 1":

• Minimum space needed: 3 + 1 + 1 = 5 cells. There's only ONE arrangement: ■■■ _ ■
• All cells are fully determined just from this clue.

Now a 6-cell row with clue "3 1":

• Two possible arrangements: ■■■ _ ■ _ and ■■■ _ _ ■
• The first 3 cells are definitely filled (overlap). Cell 4 is definitely empty. Cells 5-6 are uncertain.
• Apply column data to resolve cells 5 and 6.

---

Puzzle Sizes and Difficulty

PlayBrain's Nonogram (Pixel Logic) includes puzzles from 5x5 up to larger grids. If you're new to Picross, start with the smallest size and apply the overlap technique first. You'll be surprised how far that single rule takes you.

---

Nonogram vs Sudoku: Which Is Harder?

They're both constraint-based logic puzzles, but they feel different. Sudoku has a fixed structure (9x9 grid, numbers 1-9 per box). Nonogram grids vary in size and clue density — a 20x20 nonogram is significantly more complex than a 5x5 despite being "the same puzzle type."

For pure beginner accessibility, Sudoku's rules are slightly easier to explain. For visual satisfaction (you draw a picture by solving), nonograms win easily.

If you enjoy nonograms, you might also like:

• Sudoku — number logic puzzle, different constraint system
• Futoshiki — grid logic with inequality constraints
• Minesweeper — probabilistic grid deduction

*Related: Best Free Puzzle Games 2026 | Sudoku Tips & Strategy*