6×6 Nonogram Solver — Step-by-Step Solutions for Every Configuration

The 6×6 Nonogram Solver processes any valid 6×6 Japanese crossword, Griddler, or Picross clue configuration and returns the complete solution — or, for puzzles requiring hypothesis testing, the step-by-step logical path through which the solution is reached. The solver applies the same constraint-propagation and hypothesis-selection algorithms used by advanced human solvers, making it a precise and transparent tool for both unblocking specific puzzles and understanding the logical structure of 6x6 configurations.

How to Use the Solver

Step 1 — Enter your clues: Input the clue sequences for all 12 lines of your 6×6 puzzle — the row clues in order from top to bottom, and the column clues from left to right. Each clue is entered as a space-separated sequence of numbers (e.g., "3 2 4" for a three-block clue). The solver validates each entry against the line length to catch input errors before processing begins.

Step 2 — Run the solver: Click Solve. The solver processes your 36-cell configuration through its constraint-propagation and hypothesis-selection algorithm and returns the complete solution grid, with each cell clearly marked as filled or empty.

Step 3 — Review the solution path: The solver displays not just the final solution but the step-by-step logical path used to reach it — which lines were resolved in which order, which constraints forced each cell confirmation, and (for Expert through Evil configurations) which hypothesis cells were selected and what cascade they produced. This step-by-step output is the primary learning tool the solver provides.

Step 4 — Return to playing: Use the solution path to identify where your own solving approach diverged from the optimal path, then return to the puzzle and continue from your current position — or start a fresh puzzle with improved technique. The solver is designed to accelerate your development as a 6x6 solver, not to replace the solving experience.

How the 6×6 Solver Algorithm Works

Initialisation phase: For a 6×6 grid, the solver initialises 12 line constraint sets across 36 cells. Six-cell lines can carry multi-block clues with meaningful slack, and the solver computes all valid arrangements for each line before beginning propagation — ensuring no arrangement is incorrectly eliminated during the constraint-reduction phase.

Constraint propagation phase: Constraint propagation proceeds across all 12 lines in parallel. The solver applies a breadth-first propagation strategy: after each round of confirmations, all newly affected lines are added to the processing queue and resolved in arrangement-count order — lowest first — to maximise information flow per propagation step.

Hypothesis resolution phase: For configurations resisting full propagation, the solver identifies the optimal hypothesis cell using a minimum-remaining-values heuristic: the cell participating in the two lowest-arrangement lines simultaneously. Both assumption branches are traced in parallel; the branch producing the first contradiction confirms the opposite assumption, which is then propagated through the full 12-line network.

Accuracy and Reliability

The 6×6 solver is guaranteed to find the unique solution to any well-formed 6×6 nonogram — a puzzle constructed so that exactly one cell configuration satisfies all clue constraints simultaneously. For puzzles with ambiguous clue sets (where multiple valid solutions exist), the solver identifies the ambiguity and reports which cells have multiple valid states rather than selecting arbitrarily among valid solutions.

All solutions returned by the solver are verified against the complete clue set before display — ensuring that the solution reported is always valid, never partial, and never the result of an incorrect hypothesis branch that was not properly resolved.

When to Use the Solver

The solver is most valuable in four specific situations:

Blocked at a specific point: You've applied every technique you know to every 6x6 line and cannot identify the next confirmed cell. The solver identifies the exact next deduction — whether a standard elimination or a hypothesis step — and explains why it follows from the current constraint state.

Learning hypothesis technique: You're developing hypothesis-and-verify skills and want to compare your hypothesis selection to the solver's. The solver's hypothesis target, assumption direction, and cascade sequence provide a concrete benchmark for evaluating your own selection strategy.

Verifying a partial solve: You want to confirm that your current grid state — with some cells already confirmed — is consistent with the unique solution before investing further time in the puzzle.

Post-solve analysis: You've completed the puzzle independently and want to understand whether the path you took was optimal — or whether there was a shorter sequence of deductions that would have reached the same solution in fewer steps.

Play 6×6 Nonograms

Ready to put the solver's insights into practice? The 6×6 puzzles are available across all six difficulty levels:

→ 6×6 Easy → 6×6 Medium → 6×6 Hard

→ 6×6 Expert → 6×6 Extreme → 6×6 Evil