rootnine games

Nonogram — rules and strategy

Read the edge numbers, find the picture

What this is

Numbers run along the edges of a 5×5 grid. Using only those numbers, work out which squares to fill. Also known as Picross or Griddlers.

Each number is the length of a run of filled squares, in order.

Your score is the time taken.

Controls

Each tap cycles the square: empty → filled → × (not here) → empty.

The × is your own note meaning “this is definitely blank”. It is not scored — the puzzle is solved the moment your filled squares match the answer. Marking them anyway makes the remaining squares far easier to see.

There is always exactly one answer. Every board is solved before it is served, and only puzzles with a unique solution are used. You never have to guess.

How to solve

Start with 5

A line marked 5 is completely filled. On a 5×5 board that is the best opening. Filling it gives you one known square in each of the five crossing lines.

Fill the overlap

Even when a run could sit in several places, some squares are always covered. On a 5-long line marked 4, whether the run sits left or right, the middle three are filled either way. Fill those first.

The arithmetic is simple: subtract the number from the line length, and trim that much from each end of the run. For 4, 5 − 4 = 1, so only one square at each end is uncertain and three in the middle are certain.

Add up the clues

Add the numbers, then add the minimum gaps needed between them. If the total equals the line length, there is only one arrangement and you can fill the whole line at once.

2 2 gives 2 + 1 + 2 = 5, so it must be ■■□■■. 1 3 gives 1 + 1 + 3 = 5, so ■□■■■.

Use × aggressively

When a line’s clues are fully satisfied, everything else in that line is ×. Marking them collapses the options when you read the crossing lines. Fast solvers mark as many × as they fill squares.

Alternate rows and columns

Reading only rows gets stuck fast. After completing a line, re-read every crossing line. The one square you just placed usually resolves the ambiguity there.

Daily challenge

A new picture opens every midnight (KST) and everyone solves the same one. Since only uniquely-solvable puzzles are served, it comes down purely to how fast you read them.

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