Printable slitherlink
Slitherlink grids in PDF, from 5 × 5 to learn the rule to 10 × 10 for regulars. Slitherlink is a logic puzzle played on a lattice of dots: you join neighbouring dots to draw one closed loop, and each number tells how many sides of its cell the loop uses. It is also known as the loop puzzle or fences. Every grid has a single solution; the solutions are on the last pages.
How it works
Pick the size and the difficulty
Sizes go from 5 × 5 to 10 × 10 cells. On easy, more than half of the cells carry a number and the basic rules are enough. On medium, you have to reason about the inside and the outside of the loop. On hard, there are as many numbers as on medium, but you sometimes have to test a line and see whether it leads to a dead end.
Set up the booklet
Choose the number of grids, A4 or Letter paper, and whether solutions are added. Six 5 × 5 or 7 × 7 grids fit on a page, four at 10 × 10, with cells of at least 8.5 mm so there is room to draw.
Print and play
Draw the lines you are sure of in pencil and put a small cross on the sides the loop does not use. Start with the 0s, whose four sides are crossed out, then with the 3s next to a 0 or in a corner.
Printing tips
Choose “Actual size” or “100%” in the print dialog, not “Fit to page”, to keep cells big enough to draw between the dots. Black and white is enough: dots and numbers are black, and on the solution pages the loop is a thick line with the numbers in grey. Use a sharp pencil and an eraser, because a line drawn too quickly often has to go. Ordinary 80 gsm paper is fine. For a class or a club, print the solution pages on a separate sheet and keep it.
Frequently asked questions
What are the rules of slitherlink?
You join neighbouring dots with horizontal or vertical lines to form one single closed loop. The loop never crosses itself and never splits: each dot has either two lines or none. A number from 0 to 3 in a cell tells how many of its four sides belong to the loop. A cell without a number may have any number of sides drawn.
Where do I start a grid?
Cross out the four sides of every 0. A 3 next to a 0 then has its three other sides drawn. A 3 in a corner of the grid must have both of its border sides drawn, and a 1 in a corner has both of its border sides crossed out. Then look at each dot: once it has two lines, the other sides leaving it are crossed out; if it has one line and only one free side left, that side is drawn.
What does the difficulty level change?
The level depends on the technique you need, not just on how many numbers are printed. An easy grid is solved with the rules of numbers and dots. A medium grid asks you to work out which cells are inside and outside the loop, and never to close a small loop too early. A hard grid sometimes makes you suppose a line and see whether it leads to something impossible.
Does each grid have a single solution?
Yes. Every grid is checked before layout: exactly one loop respects all the numbers. If you find two ways to finish, a mistake crept in earlier.
From what age can you play?
Around 9 or 10 for an easy 5 × 5 grid, which takes 5 to 10 minutes. A 7 × 7 grid takes 10 to 20 minutes, a hard 10 × 10 grid half an hour and more.
Can I use them in class or in a club?
Yes, freely, including printing them in quantity. Only reselling the files is not allowed.
Are my settings saved?
On your device only, so you get the same size and difficulty next time. Nothing is sent to a server.