Comparison · Distant to Sudoku

Sudoku vs Nonogram

Nonogram is also known as Picross, Griddlers, Hanjie, Paint by Numbers

A grid where number clues on each row and column tell you the lengths of filled runs, revealing a hidden picture.

Sudoku and Nonogram are both grid-based logic puzzles you solve by pure deduction, so solvers naturally wonder how alike they really are. The short answer: Nonogram is distant to Sudoku. Below we lay out what the two share, where they part ways, and whether the skills you have built on Sudoku will carry over.

  • Grid: Variable rectangle
  • Closeness to Sudoku: Distant
  • Also called: Picross, Griddlers, Hanjie, Paint by Numbers

What is Nonogram?

A grid where number clues on each row and column tell you the lengths of filled runs, revealing a hidden picture. Here are the rules in full:

  • Each row and column has a sequence of numbers giving the lengths of consecutive filled blocks, in order.
  • Blocks in the same line are separated by at least one empty cell.
  • You shade cells in or mark them empty until every clue is satisfied and a picture emerges.

See a Nonogram picture

A Nonogram is solved by shading cells according to the number clues on each row and column, until a picture appears. Below, the clues have been solved to reveal a simple plus sign.

A finished Nonogram: shaded cells (from the row and column clues) form a picture.

Nonograms share Sudoku's pure-logic, single-solution spirit and the habit of marking what a cell can't be - but almost none of its mechanics. There are no digits to place: you shade cells from run-length clues, and the reward is a picture rather than a filled number grid. It's the most distant relative in this list.

What Nonogram shares with Sudoku

  • Both are grid puzzles solved by pure logic with exactly one solution - never by guessing.
  • Both reward marking what a cell can't be as much as what it is.
  • Overlap reasoning in a Nonogram line rhymes with candidate elimination in Sudoku.

How Nonogram differs from Sudoku

  • Nonograms are black-and-white, not numbers - you fill or leave blank, never place 1-9.
  • Clues are run-lengths, and rows and columns are independent, with no boxes or Latin-square rule.
  • The payoff is a picture, not a completed number grid.

Do Sudoku skills transfer?

Little transfers mechanically - there are no digits to place - but the mindset does: work each line for forced cells, mark impossibilities, and never guess. That "logic-only, prove every cell" discipline is exactly what Sudoku trains.

The verdict

A Nonogram shares Sudoku's pure-logic spirit but almost none of its mechanics - it's a picture-painting puzzle, not a number-placement one.


Where to play it

If it was Sudoku you came for, the level is the choice that matters more than the variant - Nonogram and Sudoku part ways on the rules, but a Sudoku grid can be a two-minute warm-up or an hour of work depending on nothing but how much of it you are given.

Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Easy Sudoku leaves 36 of the 81 cells filled, so there is always an obvious next move somewhere; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.

About Evil Sudoku

Nonogram vs Sudoku - FAQ

Is a Nonogram harder than Sudoku?
Neither is harder as a class - both run from trivial to expert depending on the puzzle, and the two ask for different reasoning. A Nonogram is solved a line at a time: you work out where a run of shaded cells can start and end, and shade the overlap that every position shares. A Sudoku is solved cell by cell, by ruling candidates out. What does differ is scale - a Sudoku is always 81 cells, while a Nonogram grows with its grid, and a 25x25 leaves fifty lines to re-check after every move.
What do Nonograms and Sudoku have in common?
Both are solved by logic rather than arithmetic, both are built to have exactly one solution, and in both the useful move is usually proving what a cell CANNOT be. Overlap reasoning in a Nonogram line is the same habit as candidate elimination in a Sudoku row.
Does a Nonogram ever need guessing?
A well-formed Nonogram has one solution and is meant to be reachable by logic, exactly like the puzzles here - though some published Nonograms do need a deeper search than line-by-line reasoning. Every Sudoku on SudokuStreak is checked to be finishable with the techniques the Sudoku School teaches, so guessing is never required.

Come for Nonogram, stay for Sudoku

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