How to play Rowcall
Rowcall is a daily picture logic puzzle, also known as a nonogram, paint by numbers or hanjie. Number clues at the side of every row and the top of every column tell you which tiles to fill. Fill the right ones and an abstract picture appears. A puzzle takes one to ten minutes.
The rules
- Each number is a run of that many filled tiles side by side. A clue of 3 1 means a run of three filled tiles, then later a single filled tile.
- Runs keep their order: left to right for a row, top to bottom for a column.
- Runs in the same line never touch. At least one empty tile sits between them.
- Every other tile in the line stays empty. The puzzle is solved when every row and column matches its clue.
Every puzzle has exactly one answer, and you can always reach it by working on one row or column at a time.
Controls
- Tap once to fill a tile.
- Tap twice to cross it out instead, your note that the tile stays empty. A third tap clears it.
- Drag along a row or column to paint the mark of the first tile on every tile you pass. Dragging from a blank tile fills, dragging from a filled tile crosses out.
- On a keyboard: arrow keys move, Space cycles a tile, F fills it, X crosses it out, Backspace clears it. The clues of the row and column you are on light up.
- Hint highlights the next tile you can prove, names the row or column that proves it, and explains why.
- When your marks can't match a clue anymore, that clue turns red.
Five techniques that solve every board
Every Rowcall puzzle can be finished with the moves below, one line at a time. Easy boards open up after a couple of passes. Hard ones make you go back and forth between rows and columns many times, each pass giving only a tile or two.
1. Lines that fit exactly
Add up the numbers in a clue, plus one gap between each pair. If the total equals the width of the board, there is only one way to place the runs: fill them in from end to end. A clue of 3 1 on a 5-wide row is 3 + 1 + 1 gap = 5, so the row is fully decided. So is 2 2.
2. The overlap
Picture a run pushed as far left as it can go, then as far right. The tiles it covers in both positions are filled whatever happens. A 4 on a 5-wide row always covers the middle three tiles. A 3 always covers the middle one. The longer the run, the bigger the overlap. With several runs, push all of them to the left together, then to the right, and compare each run with itself.
3. Out of reach
Once a line has a filled tile, its run can only stretch so far from it. Tiles that no run can reach in any position stay empty, so cross them out. This matters most near the edges and next to crosses, which block a run just like the edge of the board.
4. Finished lines
When a line already has all of its runs, every other tile in it is empty. Cross them out right away: the crosses give the crossing columns or rows something to push against. Turn on Auto crosses in settings and the game does this for you.
5. Try every fit
On hard boards, slide the runs through every position they could still take around the tiles you already know. A tile that is filled in every possible arrangement is filled; a tile that is empty in every one stays empty. Start with short lines that have a few known tiles, where there are only a handful of arrangements to check. Then switch direction: every new tile in a row is a new clue for its column.
Questions
When does a new puzzle come out?
At midnight in your own time zone. The board grows through the week, from 5×5 on Monday to 10×10 at the weekend.
Do I need an account?
No. Your streak, times and progress are saved in this browser. Clearing browser data removes them.
Does using a hint break my streak?
No. Your result just shows how many hints you used.
Is Rowcall a nonogram?
Yes. The rules come from the classic nonogram, also called paint by numbers or hanjie. Rowcall has its own boards made by our own generator: abstract patterns rather than drawings, a new puzzle every day, 300 practice puzzles and step-by-step hints.
Can a puzzle need a guess?
No. Before a puzzle is published, a solver works through it one row or column at a time with the techniques above. If it ever gets stuck, the puzzle is changed or thrown away. A separate check confirms it has exactly one answer.
Do the crosses count?
No. Crosses are notes for you. The puzzle is solved as soon as the filled tiles match every clue.