Play, solve, make and print nonograms

Slitherlink

Draw one closed loop between the dots; each number says how many sides of its cell the loop uses.

Slitherlink is a logic puzzle where you draw one closed loop along the lines of a grid of dots, guided by numbers placed in some of the cells. This free slitherlink game runs in your browser, so there is nothing to install. Each slitherlink puzzle on this page has exactly one solution, so it can be solved by reasoning. The puzzle is also known as Loop the Loop, Fences or Takegaki, and it is a Nikoli puzzle. Use the controls above the board to pick a size and difficulty, then start drawing. If you searched for slither link or a loop puzzle, this is the same game. No account or sign-up is needed, and it works on phones, tablets and computers. Puzzles you print here are free to use in class or in products you sell, such as KDP books.
Slitherlink example
  1. Above the board, choose a size (5×5, 7×7, 10×10 or 12×12; the default is 7×7) and a difficulty (Easy, Medium or Hard). Press New puzzle and wait for “Generating…” to finish.
  2. Click or tap between two dots to draw a line. Click the same edge again to remove it.
  3. Drag along several edges to draw them all at once.
  4. Right-click, or use the X chip, to mark an edge you know is empty.
  5. Watch the numbers. A number turns grey when it is satisfied. Red marks show a rule break.
  6. Press Hint when you are stuck. It highlights the cells involved and explains the next step in one sentence.
  7. Press Check to see wrong marks in red, or to see how much of the puzzle is done.
  8. When the loop is finished, the page shows “Solved in m:ss” and how many hints you used.

Keyboard players can move between dots with the arrow keys, draw or erase a line in a direction with Shift+arrow, and clear the lines around a dot with Backspace. Undo and Redo work with Ctrl+Z and Shift+Ctrl+Z (Cmd on a Mac). Press Print for a page with the size, difficulty and rules, and tick “Print the answer page too” to add the solution. Copy link gives you a link that opens the exact same puzzle on another device.

The board is a grid of dots, and some cells hold a number 0, 1, 2 or 3. Draw lines between neighbouring dots so that they form one single closed loop that never crosses itself or branches. Each number says how many of its cell’s four sides belong to the loop, and cells without a number can have any count.

Start with the basic rules, which are enough for Easy puzzles. Put X on all four sides of every 0, because a 0 has four empty sides. A number whose lines are all drawn gets X on its other sides, and a number that needs every open side gets lines on all of them. A dot with two lines has no more, and a dot with one line and only one way out must continue that way. A dot with no line and only one open edge leaves that edge empty, since a line there would be a dead end.

Medium puzzles also need the intermediate techniques. A 3 in a corner has lines on both outer sides, and a 1 in a corner has none there. Two 3s side by side have lines on the shared side and on both outer parallel sides. Two 3s touching at a corner have lines on the two sides of each 3 that lead away from the shared dot. For any number, try each way of drawing its sides and drop the ones that leave a loose end or three lines at a dot. An edge that would close the loop too early must stay empty.

Hard puzzles need trial and error. Try an edge as a line, follow the rules, and see whether they contradict. If they do, that edge must be empty. As a worked example, the first hint on a 5×5 Easy puzzle (seed 3) says: “The number 0 already has all its lines, so its other sides cannot be lines.” Hints like this usually start with the 0s, so that is a good place to begin.

Frequently asked questions

A slitherlink is a loop puzzle played on a grid of dots. You draw one closed line through the dots, and the numbers in some cells tell you how many sides of that cell the loop uses.

On small grids, it is quick once you know the basic rules. The difficulty comes from the rule that there must be one single loop, so Hard puzzles often need you to try an edge both ways. Start on Easy and move up as you learn the techniques.

Is it free, and do I need an account?

Yes, it is free. You do not need an account or sign-up, and nothing is uploaded. Your progress and settings are saved in your browser and restored when you come back.

Can I play on a phone?

Yes. It works on phones, tablets and computers. On a phone or tablet, the Line and X chips choose what a tap does, and the Move chip lets you scroll a zoomed board.

Can I print it?

Yes. Press Print to get the puzzle on its own page with its size, difficulty and rules. Tick “Print the answer page too” to add the solution on a second page, and choose Save as PDF in the print dialog if you want a file. A4 and Letter both work.

Does every puzzle have one solution?

Yes. Each puzzle is generated in your browser from a random seed and kept only if the site’s own solver proves it has exactly one solution. That means it can always be finished by logic, without guessing between two answers.

Are slitherlink puzzles from this page free for commercial use?

Yes. Slitherlink puzzles from this page are royalty-free for personal, classroom and commercial use, including puzzle books on Amazon KDP, printables on Etsy, Teachers Pay Teachers and Gumroad. No credit is required. The only thing you may not do is copy the generator or the site itself to run a competing service; see the terms.

  • Masyu: Use it if you enjoy drawing a single loop through marked cells, with a different set of turning rules.
  • Bridges puzzle (Hashi): Try it if you like connecting numbered islands with a fixed count of lines.
  • Star Battle: Choose it for another grid logic puzzle where you place stars under row, column and region limits.
  • Nonogram: Play it when you want to fill a grid from number clues on each row and column.
  • Binary puzzle (Binairo): Pick it for a quick grid puzzle that uses simple placement rules.
  • Shikaku: Try it to split a grid into rectangles whose areas match the numbers.
  • Nurikabe: Choose it to shade a connected wall around numbered islands.
  • Slitherlink solver: Use it to type in a puzzle from a book or app and get its loop and solving steps.