Printable Jigsaw Sudoku Puzzles

What’s in the free jigsaw sudoku PDFs?

Four files, one per level, each holding 100 jigsaw sudoku puzzles — 400 in all, every one with exactly one answer. Each PDF runs to 63 US Letter pages: a cover with the rules, the puzzles two to a page on pages 2 to 51, and the answers nine to a page on pages 52 to 63. The buttons above are the files themselves, about 420 KB each, with no email and no signup.

Jigsaw sudoku, also sold as irregular, nonomino or squiggly sudoku, is classic sudoku with the nine 3×3 boxes swapped for nine irregular regions: every row, column and region holds 1 to 9 once. The Jigsaw Sudoku game page covers the rules and strategy in depth; this page is about paper. Other variants are on the printable sudoku page.

Easy, Medium, Hard or Expert: which level should you print?

We ran all 400 printed puzzles through a solver that tries one technique at a time, easiest first:

All 100 puzzles of each PDF. The solver tries singles, then region-line locks (“lock”), then pairs and triples, then one-digit patterns such as the X-Wing and skyscraper (“pattern”); each puzzle is counted under the hardest step it used. “Open at first look”: the median number of cells a single settles before anything is written in. The 9 beyond our solver still have exactly one answer.

Easy and Medium are singles puzzles with odd-shaped boxes. Naked and hidden singles finish every Easy puzzle and 97 of the Medium ones. What changes is how you find them: filling the cells where only one digit fits finishes 92 Easy puzzles, 60 Medium and just 2 Hard. Past that you chase one digit at a time through a row, a column or a region.

Hard and Expert are where the shapes bite. A fifth of the Hard puzzles and nearly half of the Expert ones need more than singles, most often a region-line lock, the jigsaw form of locked candidates. Expert Puzzle 63, on page 33, gives you nothing at first look: no cell is down to one digit, no digit is down to one place in any row, column or region, and our solver has to open it with a lock.

Where do you start on a printed jigsaw sudoku?

Paper has no conflict highlighting, so the dependable opening is the one below: pick a digit and follow it through one region. A region almost always touches more rows and columns than a 3×3 box (only 16 of the 3,600 regions in these PDFs are 3×3 squares), so the digits around it strike its cells from more directions. Of the 400 printed puzzles, 360 have at least one cell at first look that only a region scan finds.

A digit you write in is a clue for the next region: after each placement, look along its row and column for a region it now pins, as the 8 did here. When singles stop on a Hard or Expert sheet, most puzzles get going again with a region-line lock, which the game page works through on a real board.

How do you print jigsaw sudoku so the regions stay clear?

• Black and white is what they are drawn for. Each region is outlined in bold and filled with white or one of three light greys, the darkest about 22% grey, and two regions that touch never share a shade.
• Use normal quality, not draft or toner-saving. Economy modes can wash out the lightest grey; the bold outlines still carry every region if they do.
• A4 works. The files are US Letter. On A4, choose Fit to page in the print dialog, which shrinks each sheet by about 3%.
• Print only the pages you need. Puzzles 1 and 2 are on page 2, 3 and 4 on page 3, and so on; the answers run nine to a page from page 52. Puzzle 37 is on page 20 and its answer on page 56.

Can you use jigsaw sudoku in a classroom?

The Easy set suits a class. All 100 puzzles fall to singles, so nobody meets a step they haven’t been shown, and the cover states the rules in two sentences, so a stapled copy explains itself. Give everyone the same puzzle number and the shading becomes a shared language: “the darkest region, top right” is somewhere anyone can point to. Print pages 52 to 63 separately and keep them back for marking.

Medium is the step up. 97 of its puzzles still need only singles, but on 40 of the 100, counting what fits each cell is no longer enough and students have to scan by digit.

How do you check your answers?

The answer key is at the back of every PDF, each grid drawn with the same bold outlines and shading as its puzzle, so you can check one region or one row without reading the rest of the solution.

If a region doesn’t match, look first for a cell you credited to the wrong region, and trace the bold outline round it. Solving a jigsaw from a newspaper or book with no key? Draw its regions into the Jigsaw Sudoku solver: it solves the grid and tells you whether it has more than one answer.