Rules
The grid starts empty. The clues sit to the left of each row and above each column. You fill cells you know are in a block, and you cross cells you know are empty.
- Blocks, in order. Each number is a block of that many filled cells. In a row they run left to right. In a column they run top to bottom. The blocks stay in the same order as the numbers.
- A gap between blocks. Two blocks in the same line have at least one empty cell between them. Empty cells may also sit before the first block and after the last.
- A blank line. A line with no numbers is empty. Cross every cell.
- Fill and cross. Fill a cell you know is in a block. Cross a cell you know is empty. A cross is your note. It is not part of the printed clue.
- Row and column together. The picture is done when every row and every column matches its clues. The same cell belongs to both.
One reading of clues 2 1. Cells 2 and 3 are the 2, cell 5 is the 1, and cell 4 is the gap. The 2 and the 1 can both slide, so this colouring is not the only one.
Every Nonogram on PuzzleKite has exactly one solution, and you can reach it by logic. You never need to guess. Easy, medium and hard are the size settings on the board: they describe which kind of step finishes the grid.
Slides and the count
Blank lines and full lines come first. Slide each block to both ends and fill the cells covered both ways. When the filled cells add up to the clues, cross the rest of the line.
Empty lines and full lines Easy
Do these before anything else. Each one is finished in a single look.
No numbers. Cross all five cells.
A 5 in a row of 5 fills cells 1 to 5.
Simple boxes Easy
Slide each block as far left as it fits, and as far right as it fits. Cells covered both ways are filled. For one clue of k cells in a line of n, that is the middle 2k − n cells, when twice the clue is longer than the line. The ends stay unknown until something else fixes them.
The smallest box
A 3 in five cells covers cell 3 either way. Cells 1, 2, 4 and 5 can still go either way, so leave them blank.
The rest of an easy grid is these marks, the count in the next section, and the same marks read down the crossing line. The later sections are the moves you need when the two slides still disagree.
When the count is met Easy
Add the clues. When that many cells are already filled, cross every unknown cell in the line. The other half of the same count: when the cells you have not crossed are exactly the clue sum, fill all of them.
Auto-cross writes these crosses for you. It is on by default. This is the whole line. A later section is different: one clue is finished and another clue is still waiting, so the sum has not been reached and these slides write nothing.
Cells out of reach
Cross a cell no block can still use: a cell every placement misses, a block stuck to one end, a pocket that is too short, the cell beside a finished clue, and the cells that join or split a block.
Cells no block can reach
Once a cell is filled, throw away every placement that misses it. A cell that is empty in all the placements that remain is a cross, even when the block can still slide. The two end slides do not always see these crosses. This is the first move that an easy grid’s two slides miss.
Edge forcing Easy
A filled cell near the end of the line sticks the block to that end. Sometimes called glue. Fill every cell the block then has to cover, and cross the cell just after a block that is now finished.
A gap that is too small
A cross splits the line into pockets. A pocket shorter than every clue that could still sit there is empty. If the other pocket is exactly the clue, the block fills it. If the other pocket is longer, the block still slides, and the short pocket is a cross the two end slides can miss.
A finished clue
When one block is finished and another clue is still left, cross the cell beside the finished block. The count from section 2 has not been reached, so this cross is not auto-cross. Both neighbours of a finished 1 are empty, because a 1 cannot grow.
Joining and splitting
Joining Easy
Two fills that a single clue has to cover are one block. The cells between them join it, and the cells after the block are empty.
Splitting
Two fills that cannot belong to the same block need a cross between them. The first 2 that covers cell 2 ends by cell 3. The second 2 that covers cell 6 starts at cell 5 or later. Cell 4 is the cell between those two reaches. The tail is empty because both blocks are already accounted for further left.
The crossing line Easy
A cell you fill or cross in a row is new information for its column, and the other way around. After each line, read the lines that share those cells. Easy puzzles are this loop with the two slides and the count. Medium and hard use the same loop with the crosses from the sections above. On 10×10 and up, hard means the loop runs longer, not that you try a cell.
First move
The plus from the rules, still empty. Row 3 is a 5, so that row fills. Column 3 is also a 5 and would fill itself with no help, so it is not the example of a row telling a column something new.
The row tells the column
Row 3’s fill puts column 1’s only black cell in place, so the rest of column 1 is empty. A blank column with clue 1 forces nothing until that cell is known. Columns 2, 4 and 5 do the same thing.
On a medium grid the mark you carry across is often a cross from the sections above, not only a fill from the two slides.
What if 5×5 hard
Use this only when every row and column has stopped. Pick one unknown cell. Try one colour. If following the lines runs into a row or column that cannot hold its clues, that colour is wrong, so write the other colour. Then go back to the lines.
On this site the only puzzles that need the step are some 5×5 hard grids, and each of them needs it once. A 10×10, 15×15 or 20×20 hard grid still finishes by lines. If a large grid feels stuck, there is a line you have not read, not a guess to make.
Row 1 is 1 1. Cross cell 2 and follow the lines. Row 3 cannot hold a 2.
- Row 1 now starts with two crosses. The only fit in the last three cells is fill, cross, fill.
- Column 2 is 2 1. Row 1 is empty, row 2 is filled, row 4 is crossed and row 5 is filled. The 2 has to be rows 2 and 3, so row 3 column 2 fills.
- Column 3 is 2 1. Rows 1 and 2 are filled, row 4 is crossed and row 5 is filled. The 2 is the top pair, so row 3 column 3 crosses.
- Column 4 is a single 1, and row 3 column 4 is the only cell still open, so it fills.
- Column 5 is 2 1, the same shape as column 3, so row 3 column 5 crosses.
- Row 3 is now cross, fill, cross, fill, cross against a clue of 2. No two filled cells can touch. The empty colour is wrong, so cell 2 of row 1 is filled. The lines then finish the picture.
Row 1 is a 2. Fill cell 2 and the block sticks. A later row is left with two filled cells touching under clues 1 1.
- The 2 is cells 1 and 2, or cells 2 and 3. Cells 4 and 5 are past both, so they cross.
- Column 2 is 2 1. Rows 1 and 2 are filled, row 4 is already crossed and row 5 is already filled. The 2 is rows 1 and 2, so row 3 column 2 crosses, and row 5 is the 1.
- Column 4 is 2 1. Row 1 is now crossed and row 2 is filled, so the 2 is rows 2 and 3, row 4 crosses, and row 5 fills.
- Column 5 is 1 1. The same pass fills rows 3 and 5 and crosses row 4.
- Row 3 is now empty, cross, empty, fill, fill against clues 1 1. Cells 4 and 5 are one block of 2. Both clues are 1s. The filled colour is wrong, so cell 2 of row 1 is a cross. The lines then finish the picture.
A shorter death. Row 1 is a 2. Cross cell 2, and row 3 is left with two open cells that do not touch.
- Row 1 now starts with two crosses. A 2 in the remaining three cells fills the middle one, so cell 4 fills.
- Column 2 is 1 2, with row 1 empty and row 4 already filled. The 1 has to sit above the 2, and the 2 cannot be rows 3 and 4, because that would touch the 1. So the 2 is rows 4 and 5, row 3 column 2 crosses, and the 1 is row 2 column 2.
- Column 4 is a single 1. With row 1 column 4 filled, that 1 is placed, and rows 2, 3 and 5 in the column cross.
- Row 2’s new fill, with clue 1, crosses the rest of row 2 that is still open.
- Row 3 is now empty, cross, cross, cross, empty against a clue of 2. The two open cells are not next to each other. The empty colour is wrong, so cell 2 of row 1 is filled. The lines then finish the picture.
Common mistakes
Each red mark is a line that cannot hold its clues, except the early cells of a 7, which are only a guess.
What to play next
Each setting adds a kind of step. The links open a real size.
- EasySlides and the countSlide each block to both ends and fill the cells covered both ways. Cross a line once its filled cells add up to its clues. Then read the crossing line. Blank rows, full rows, and lines whose clues pack the width are the opening.Play Easy →
- MediumCells every placement leaves emptyThe two end slides are not enough. Cross a cell that every remaining placement leaves empty: a tail past a block, a pocket that is too short, the cell beside a finished clue, the gap that splits two fills.Play Medium →
- HardA longer loop, or one what-ifOn 10×10, 15×15 and 20×20, hard is the same line logic with more trips between rows and columns. On 5×5, hard is one what-if, then the lines finish.Play Hard →
Grids come in 5×5, 10×10, 15×15 and 20×20. On 5×5, hard is one what-if: open a 5×5 hard grid. The daily puzzle is a 10×10 easy grid, the same one for everyone that day: today’s daily or a 10×10 easy board. For pencil and paper, print a Nonograms pack.