Guide
How to Play Jigsaw Sudoku
Jigsaw Sudoku (Loco Sudoku) is sudoku with irregular regions. Fill the 9x9 grid so every row, column and coloured region holds the digits 1 to 9 exactly once.
Play Jigsaw SudokuThe objective
Every row, column and region holds 1 to 9 once
Jigsaw Sudoku is played on a 9x9 grid with some digits already filled in. Your job is to fill every empty cell so that no digit repeats in any row, any column, or any of the nine coloured regions. When the last cell is correct, the puzzle is solved and the clock stops.
If you can play classic sudoku you already know the rules; the only change is the shape of the groups. If you are new, everything you need is on this page. Every puzzle has exactly one solution and can be solved by logic alone — there is never a reason to guess.
The game is free, runs in the browser, and needs no account. Open the board when you want to play.
The regions
Nine irregular shapes instead of nine boxes
In classic sudoku the nine 3x3 boxes are the third constraint. Jigsaw Sudoku replaces them with nine connected regions of nine cells each. They can be long and thin, L-shaped, or wrap around one another, and each has its own colour tint plus a thick border, so you never have to rely on colour alone.
Select any cell and its row, column and region are highlighted together, and every cell holding the same digit lights up in amber. Because two cells of one region need not share a row or column, check all three groups for every candidate.
Every new puzzle gets a fresh region layout, generated on your device, so the shapes you learned last time will not come back.
Controls
Tap, click, or use the keyboard
Every method does the same thing. Pick whichever fits the device in your hand.
Every device
Tap or click
Tap a cell to select it, then tap a number on the pad to fill it. The row, column and region of the selected cell are highlighted, and every matching digit on the board glows amber so you can see where a number is still missing.
On-screen buttons
Notes, undo, erase, hint
Notes switches the pad to pencil marks. Undo steps back through your moves, Erase clears a wrong digit or a cell of notes, and Hint reveals the answer for the selected cell (or a random open cell). New deals a fresh puzzle instantly with no page reload.
Desktop
Keyboard
1–9 enter a digit, the arrow keys move the selection, Backspace or Delete erases, N toggles pencil notes, U undoes, H gives a hint, Escape deselects, and M mutes the sound. Tab still reaches every button, with a visible focus ring.
Step by step
From the first digit to a solved grid
Reading the regions, spotting where a digit must go, and filling it in is the whole loop.
- 1
Read the regions
The 9x9 grid is split into nine irregular, coloured regions of nine cells each. They replace the 3x3 boxes of classic sudoku. Thick lines and colour tints mark where one region ends and the next begins.
- 2
Use the givens
Some cells start filled in bold white. Those digits are fixed. Every row, column and region needs each digit from 1 to 9 exactly once, so a given rules that digit out of its row, its column and its region.
- 3
Fill in the blanks
Select a cell and press a digit, or tap a number on the pad. Correct digits lock in amber; a digit that does not belong turns red and adds to your mistake count so you can fix it straight away.
- 4
Solve to finish
Complete the whole grid and the clock stops. Every puzzle has exactly one solution, so pure logic always gets you there — no guessing is ever required.
Rules
Every rule that decides a move
The objective
Fill the 9x9 grid so that every row, every column and every one of the nine regions contains the digits 1 to 9 exactly once. The puzzle is solved when the last cell is filled correctly.
Regions are irregular
Each region is a connected group of nine cells, but it can snake, bend and wrap around others. Two cells in a region need not sit in the same row or column, which is what makes jigsaw puzzles feel different from classic sudoku.
One solution
Every puzzle here is checked by a solver to have exactly one solution. If two cells could swap digits and still satisfy the rules, the puzzle would not be served.
Mistakes and hints
A digit that does not match the solution shows in red immediately and adds one to the mistake counter. There is no game over. Hints reveal a cell and are counted, and a solve with hints does not set a best time.
Timer and stats
The clock starts at your first move or when you press Play, and stops when you solve. Solved count, win rate, best time and streak are tracked for each level on this device.
Difficulty
Easy, Medium and Hard
Difficulty is set by how many digits are given at the start. Pick a level with the switch above the board; stats are kept separately for each.
- 01 · 38 givens
Easy
Plenty of starting digits, so most cells fall to a single "only place for this digit" or "only digit for this cell" deduction. A good first level while you get used to reading irregular regions.
- 02 · 31 givens
Medium
Fewer clues mean you will need pencil notes and the odd region-versus-line elimination. Expect to mark candidates in the tightest regions before the grid opens up.
- 03 · 25 givens
Hard
A sparse start where candidates interlock. Notes are close to essential, and you will lean on pairs and region-and-line overlaps. Still one unique solution, still no guessing.
Common mistakes
Where jigsaw puzzles go wrong
Treating regions like boxes
In classic sudoku the box is always a neat 3x3 square. Here a region can be a long thin snake, so a digit you think is "in the top-left box" may already be sitting in a cell you did not see. Trace the region with your eye, or select any of its cells to highlight it.
Forgetting the rows and columns
Because regions are oddly shaped, it is easy to focus on them and overlook the row and column constraints. Strong solves check all three groups every time.
Notes everywhere from the start
Filling every cell with candidates buries the useful information. Add notes where a cell has three or fewer options and let the singles come first.
Guessing
Every puzzle is fully deducible. If you are tempted to guess, there is a missed elimination somewhere — look for pairs, or a digit locked to one line inside a region.
Solving habits
Tips to solve faster
A summary — the full tips page walks through each technique in depth.
- Scan the smallest gaps first: a region, row or column with only two or three empty cells is where the next digit usually falls.
- Pick one digit and sweep it across the whole board. Which region, row and column already hold a 7? Where can the remaining 7s still go?
- Region shapes cut across rows and columns, so check all three groups for every cell. A cell often looks open in its region but is blocked by its row.
- Turn on Notes for Medium and Hard. Write candidates only in cells that are running out of options, not across the whole grid.
- When a digit can only appear in the part of a region that overlaps one row, that digit is not allowed anywhere else in that row.
- A wrong digit shows in red straight away. Undo it, then work out why: it usually means a region overlap you did not check.
- Use a hint to learn, not to win: reveal one stuck cell, then ask what deduction you missed.
Where you can play
Same puzzle on phone and desktop
jigsawsudoku.app runs in any modern browser with no app to install. Progress stays on the device you played on.
Desktop browsers
Chrome, Edge, Firefox and Safari all run the game with no plugin. Click cells and use the number keys, arrow keys, and shortcut letters for notes, undo, hint and mute.
Phones and tablets
The board and number pad fit above the fold on a phone in portrait. Tap a cell, tap a number, done. Restarting and switching difficulty are instant.
Progress on this device
Your puzzle in progress, plus best times and streaks per level, live in local browser storage. Refresh the page and you carry on where you left off. Nothing syncs between devices.
Still stuck on a rule? Read the Jigsaw Sudoku FAQ or jump in and play.
Play Jigsaw Sudoku free