Introduction
Nonogram is a picture logic puzzle where every row and column clue tells you how many consecutive filled cells belong in that line. As you combine those clue groups, a hidden pixel-art image appears. It is a calm puzzle format, but good boards still reward careful deduction, line overlap reading, and smart use of marks.
How to Play
Choose a difficulty, read the row and column clues, and fill cells that must be part of the picture. Use cross marks for cells that cannot be filled. On desktop, right click always places a cross, and on mobile you can switch between fill and cross modes. This version also supports undo, hints, keyboard navigation, and optional automatic marking for leftover cells when a line is logically complete.
Features
- •Very easy to colossus Nonogram boards, including 20x20, 25x25, and 30x30 puzzle packs
- •Fill mode, cross mode, right-click marking, and keyboard shortcuts
- •Hint and undo tools that help without breaking the puzzle flow
- •Automatic leftover marking when a row or column is logically finished
- •Progress, solved-line tracking, timer, and local best times
- •Responsive layout that works on desktop, tablet, and mobile screens
How Nonogram Clues Work
Each clue number describes one continuous block of filled cells. If a row shows 4 2, that row contains one run of four filled cells, then at least one empty cell, then one run of two filled cells. The exact placement is not given directly, so the puzzle comes from finding every position that still fits all clue groups at once.
A Practical Solving Flow
Start with lines that have large clue totals, because they often create overlap from both ends. Use those guaranteed cells to unlock crossings in the opposite direction. Once a line has every required filled cell placed, mark the remaining cells so your attention stays on unresolved space instead of already-finished work.
Why Cross Marks Matter
Crosses are not decoration. They reduce uncertainty, separate clue groups, and make overlap calculations much easier. On dense boards, the difference between an organized grid and an unmarked grid is often the difference between steady progress and repeated re-checking.
Difficulty and Replay Value
Small boards are great for learning clue structure, while larger boards create more multi-step deductions and longer image reveals. A good Nonogram stays satisfying because the final picture feels earned: every completed image comes from logic, not from random guessing or reaction speed.
Nonogram Control Reference
Quick reference for the main interactions in this online Nonogram.
| Action | What It Does | Best Time to Use It |
|---|---|---|
| Fill | Paints a cell as part of the picture | When a cell is logically certain |
| Cross | Marks a cell as excluded | When a cell cannot belong to any valid clue placement |
| Undo | Reverts the last move | When you want to test a line without losing your place |
| Hint | Reveals one correct next move | When the board stalls or you want a gentle nudge |
| Auto X | Optionally marks leftover cells after a line is logically complete | To keep the grid readable without forcing automatic cleanup |
Difficulty and Strategy Guide
How the puzzle feel changes as the grid gets larger.
| Difficulty | Board Feel | Recommended Focus |
|---|---|---|
| Very Easy | Small starter boards | Learn clue grouping and basic overlap logic |
| Easy | Short lines and fast image reveals | Practice overlap logic and clue grouping |
| Medium | More crossings and more ways to stall | Use crosses aggressively to separate clue runs |
| Hard | Longer chains of deductions across the grid | Work in layers and revisit lines after each new crossing |
| Expert | Large boards with slower reveals | Stay organized and revisit lines after each confirmed crossing |
| Master | 20 x 20 boards with longer clue memory | Cycle rows and columns methodically instead of tunnel-visioning one zone |
| Legend | 25 x 25 boards with sparse anchors | Use reliable anchors and protect every confirmed X mark |
| Colossus | 30 x 30 marathon boards | Break the solve into regions and keep the grid clean as clue stacks grow |
Frequently Asked Questions
What is the difference between Nonogram and Picross?
They refer to the same style of picture logic puzzle. Picross is a popular brand name, while Nonogram is the general puzzle name.
Do I need to fill every empty cell with a cross?
Crosses are not always required to understand the solution, but they make the board far easier to read. In this version, logically completed lines can auto-mark the leftover cells for you.
How do I start a Nonogram when I feel stuck?
Begin with rows or columns whose clues take up a large part of the line. Those create guaranteed overlap cells, which then open new information in the crossing direction.
Are hints and undo useful for learning?
Yes. Undo lets you test an idea safely, and hints can show the kind of move the puzzle expects next without skipping the whole board.
Can I play this Nonogram on mobile?
Yes. The layout is responsive, and the game includes dedicated fill and cross modes for touch screens.