Follow a complete five-by-five Playfield puzzle, compare legal line patterns, and practise telling a forced square from a guess.
Playfield Arcade · Updated 2 October 2026 · Fixed practice board: nonograms-2026-09-11
An unfinished Nonogram can tempt you to fill the shape you think you see. This lesson takes a different approach: every new mark follows from a number clue and the marks already established. You will finish one complete board and see why each change is necessary.
Our fixed practice board is nonograms-2026-09-11, a five-by-five puzzle from Playfield’s existing bank. It stays the same whenever you return to this lesson. It is not a claim about today’s puzzle. R1C1 means row 1, column 1; rows run downward and columns run to the right.
Start with the clues
A clue lists filled runs in order. The clue 1, 3 means one filled square, at least one empty square, then three filled squares. Extra empty squares may appear at either end or between runs. Row clues are read left to right; column clues are read top to bottom.
Unknown and empty mean different things. An unknown square has not been decided. An empty mark says the square cannot be filled. Both kinds of proven mark constrain the crossing line.
To decide a line, consider every arrangement that fits its clues and existing marks. Fill a square only if every remaining arrangement fills it; mark it empty only if every arrangement leaves it empty. If arrangements disagree, this line has not settled that square yet.
Filled squares are dark; × means empty; ? is not decided. Red outlines show what changed in a step. Clues above and beside the grid are part of the puzzle.
Coordinates count from the top left: R2C3 means row 2, column 3.
The game opens its normal saved board for this ID. This lesson does not change or clear your progress. Read the steps here or try the board first.
Follow the deductions
Every before-and-after board is included below. The optional step view shows one deduction at a time; it does not make game moves.
DEDUCTION 1 OF 10
Row 2 fits exactly
Row 2 has clues 1, 3. The runs use four squares and their required separating gap uses one: 1 + 1 + 3 = 5. Nothing can shift. Fill R2C1, mark R2C2 empty, and fill R2C3 through R2C5. The empty square is just as certain as the filled ones.
Row 3 needs a run of three in five squares. It can occupy columns 1–3, 2–4 or 3–5. All three placements contain R3C3, so fill that square. They disagree about every other square. Leave those squares unknown rather than picking the placement that looks most promising.
Row 4 has the single clue 5. Its run occupies the entire five-square row, so fill R4C1 through R4C5. This supplies a useful filled square to every column without requiring any guess about the picture.
Row 5 has the same 1, 3 clues as row 2. Again the two runs and mandatory gap consume all five squares. Fill R5C1 and R5C3 through R5C5, and mark R5C2 empty. The argument repeats because the line length and clues match, not because two rows must look alike.
Column 1 requires runs 1, 2. R4C1 and R5C1 are already filled, making the two-square run at the bottom. R2C1 supplies the earlier single square. R1C1 must be empty to avoid extending that single, and R3C1 must be empty to separate the runs.
Column 2 also requires 1, 2. R2C2 and R5C2 are empty, and R4C2 is filled. The bottom pair must therefore occupy R3C2 and R4C2; it cannot extend into row 5. The earlier single has only R1C2 available. Fill R1C2 and R3C2.
Column 3 has clue 5, so every square in it is filled. Rows 2 through 5 are already marked. Fill the remaining square, R1C3. We could have used this column earlier; a correct solve does not need to follow one special order.
Row 1 needs one run of two. R1C2 and R1C3 now provide that entire run, while R1C1 is already empty. Mark R1C4 and R1C5 empty: another filled square would either lengthen the run or create a second run that the clue does not allow.
Column 4 needs four consecutive filled squares. R1C4 is empty, so the run must occupy rows 2–5. Three of those squares are already filled. Fill R3C4 to complete the run. Notice how finishing a row created the useful restriction in its crossing column.
Column 5 has clues 1, 2. R2C5 is the single filled square, and R4C5–R5C5 form the pair. R1C5 is already empty. Mark R3C5 empty to keep the two runs apart. Every square is now decided, and row 3 reads as a run of three at columns 2–4.
Check the completed rows and columns separately against their clues. In particular, rows 2 and 5 contain two runs with an empty gap; a total of four filled squares alone would not have proved those rows correct.
This board was completed using exact fits, overlap and the consequences of earlier marks. That does not establish that every Nonogram can be solved by these simple techniques. When one line stays uncertain, inspect its crossing lines before adding an unsupported mark.
Use the Line Lab to replay a single line from this lesson. It enumerates arrangements for that line only; it does not read the rest of the board. No surviving patterns means that the clues and current marks conflict. The tool does not by itself identify when or why a mistaken assumption entered your solve.
On the playable board, Check compares your marks with the stored answer, while Hint reveals a square from that answer. Those aids can help you continue, but an answer reveal is different from the explanations above. Open the fixed board if you want to reconstruct the deductions yourself.
Check yourself
Try each question before opening its explanation. These examples separate what is forced from what merely looks possible.
Practice: when a line cannot decide
Practice line · clue 2
1?2?3?4?5?
A five-square line has clue 2 and no marks. Is any square certainly filled or certainly empty? Explain your answer without choosing a favourite placement.
Show explanation
No square is settled. The pair can occupy positions 1–2, 2–3, 3–4 or 4–5. No position belongs to every placement, and every position belongs to at least one placement. Leave all five unknown and look for information from crossing lines.
This five-square line has clues 1, 3, but position 2 is marked filled. Why are there no legal patterns? What must position 2 be?
Show explanation
The runs and required gap exactly fill the line: filled, empty, filled, filled, filled. Position 2 must be empty, so the supplied filled mark conflicts with the clue. With that mark cleared, the one legal pattern returns. On a full board, also revisit whatever earlier reasoning led you to fill it.
Return to a line or island when a crossing constraint changes. Keep undecided choices open; a plausible placement is not a proof. These selected teaching boards have the deduction sequences shown here. Other daily boards may need different techniques.