How to solve Slitherlink
Cross out the sides the loop can’t use, then let the numbers and the dots push the loop along. It draws itself one forced side at a time.
How it works
Slitherlink gives you a grid of dots with numbers in some squares. Draw one loop along the sides of the squares. Each number says how many of its four sides the loop uses. A blank square can use any number.
Two rules do most of the work. A number that has all its lines crosses its other sides, and a number that needs every side it has left takes them all. Every dot has two lines or none, so a line that reaches a dot must go on through it.
Mark the sides you rule out with ×. They are as useful as the lines, because they leave the other sides with nowhere else to go.
Where to look first
0s, then 3s. A 0 crosses four sides at once. A 3 beside a 0, or in a corner of the grid, draws lines straight away.
Then follow the ends of your lines. The end of a line is a dot that needs one more line, and it often has only one way to go.
Only one loop
A side that would close a small loop while other lines are still open is a ×. The finished puzzle is a single loop, so it can’t close early.
Worth memorizing
0s first.
Cross all four sides.
Every dot has two lines or none.
A line that reaches a dot goes on through it.
A number that is full crosses the rest.
A number that needs every free side takes them all.
Practice
0 of 4 rightThis 3 has one side crossed. What about its other three sides?
This 2 already has two lines. What about its other sides?
A dot has one line, and every other side at that dot is crossed. What does that tell you?
How many sides does the finished loop use?