Strategy Center

Nonogram Tips and Tactics

Nonogram strategy comes down to a handful of named techniques — overlap, edge logic, mercury, gap splitting. Each one turns a half-known line into guaranteed cells. Learn them here on small interactive boards, then chain them to crack any grid.

CORE PRINCIPLES

Never Guess

Nonograms are deduction puzzles, not gambling. Every guess plants a hidden error that surfaces twenty moves later, where it costs lives and morale. If a line offers nothing certain, leave it — the cells you solve elsewhere will reopen it.

Close Finished Lines

The instant a line satisfies its clue, X out everything left in it. It feels like bookkeeping, but every X is a constraint on a crossing line — experienced solvers spend as much time placing X marks as they do painting.

Kill the Too-Small Gaps

A pocket between two X marks that is shorter than every clue that could reach it can never host a block. Spot it, X it out completely, and the line gets simpler. Small gaps die quietly — make a habit of checking them.

NAMED TECHNIQUES

Overlap with Multiple Clues

You know single-clue overlap from the basics: push the block both ways and paint what is covered twice. The same logic works with several clues in one line. Pack all the blocks to the left, then to the right — keeping their order and one gap between them — and paint every cell where a block overlaps itself across the two layouts.

Try It Yourself

A 10-cell row with clues 4 and 3. Packed left they sit on cells 1–4 and 6–8; packed right, on 3–6 and 8–10. Paint only the cells both layouts share.

Edge Logic (Anchors)

A filled cell touching the border is an anchor: the block containing it can only grow inward. First cell filled with a clue of 3 means cells two and three are forced — and the one after them is a free X. The same trick works against any X, not just the wall. Every confirmed edge turns a vague clue into an exact position.

Try It Yourself

The clue is 3 and the first cell is already filled. The block can only extend right — paint the rest of it.

Mercury (Pushing Off the Edges)

Take a lone filled cell and slide its block through every legal position around it. The cells that no placement can reach are guaranteed empty. Named after how mercury pulls away from the walls of a container, this technique clears the far ends of a line without ever knowing where the block actually sits.

Try It Yourself

The clue is 3 and the fifth cell is filled. Slide the block through every position that contains it — then X the cells no position can reach.

Gap Splitting

An X in the middle of a line splits it into independent segments, and a block must fit entirely inside one segment. Measure each segment against the clue: when one side is too small, the whole clue belongs to the other — often placing it exactly. This is how a single X can collapse half a line.

Try It Yourself

The clue is 5 and an X splits the row into a 4-cell and a 5-cell segment. Five cannot fit on the left — paint where it must go.

BIG GRID STRATEGY

Hunt the Loaded Lines

On a 25x25, do not read clues in order — hunt the lines that say the most. A clue that nearly fills its line, several clues summing close to the line length, or an empty "0" line: those are free openings. Sweep every row and column once before placing anything.

Pencil In with Notes

Use the note tools for possibilities you cannot prove yet — mark where a block might start, then confirm or erase as the crossing lines fill in. Getting the "maybes" out of your head and onto the board frees you to chase certain moves.

Re-scan After Every Burst

Progress comes in waves: a few placements, then silence. After each burst, revisit the lines that cross your new cells — that is where the next wave starts. If the whole grid stalls, recheck your most crowded line; a forgotten X is usually hiding there.

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Left click to paint · Right click to mark empty · Drag to select multiple