Rules
Slitherlink is also called Fences. You draw on the lines between the dots. The goal is one loop that satisfies every number.
- One closed loop. The line joins neighbouring dots, across or down. It never branches, never crosses itself, and never stops short. Every dot on the loop has two lines. Every other dot has none.
- Match the numbers. A 0, 1, 2 or 3 says how many of that cell’s four sides are on the loop. An empty cell can have any count.
- One solution. Every grid here has exactly one loop that fits. You can reach it by the steps below. You never need to guess.
The puzzle from this guide, solved. Crosses are left off so the loop is easy to follow.
A cross is a note to yourself: that side is not on the loop. The puzzle can be finished without them. They make the next step easier to see, so use them.
First moves
Every first move is counting around one cell or one dot. On PuzzleKite, Easy grids need nothing else. Start with the 0s and the 3s.
Zeros Easy
A 0 has no line on any side. Cross all four. Those crosses are often the first marks on the board.
This 0 sits between two blanks, above the 3. All four sides are empty. Nothing else on the grid can put a line there.
Corners Easy
A corner cell has two sides on the border of the grid. A 3 there uses both of them: the only way to leave one border empty is to take all three of the other sides, and that puts three lines on the corner dot. A 1 in the corner leaves both border edges empty, for the same reason turned around. A 2 in the corner does not settle yet.
The 3 in the top-left corner uses both border edges. The other two sides stay open for now.
The 1 in the bottom-right corner leaves both border edges empty. Its one line is one of the inner sides.
Full numbers Easy
Once a few crosses are in, a number often has nowhere else to go. If the open sides are exactly the lines it still needs, draw them all. If it already has all its lines, cross whatever is left.
The 3 under the 0 already shares a cross with that 0. Three sides are still open, and it needs three lines, so all three are lines.
The corner 3 now has its three lines. The inner edge is empty. With Auto-× on, that cross appears as soon as the third line does.
Dots Easy
The same counting works on a dot. Two lines is a through-path. One line must continue along the only open edge. No line, and only one open edge, means that edge is empty: a line there would be a dead end.
This dot has no line, and the 0 beside it has already crossed the other edges. The last edge is empty.
The corner 3’s line arrives here, and one edge is still open. A loop can’t stop, so that edge is a line.
Two lines already meet at this dot on the left edge. A third would be a branch, so the last edge is empty.
No early loops Easy
An edge whose two ends already sit on the same chain of lines would close a loop. If other lines are still on the board, that loop is too small, so the edge is empty. The closing edge of the real loop is left for later, when it would finish every clue at once.
A 0 beside a 3 Easy
A 0 and a 3 that share a corner settle together. Once the 0’s crosses are in at that corner, the 3 takes the edges that remain. The first of those edges is the next Hint; the second follows at the same dot.
The 0 is already crossed on every side. It shares its bottom-right dot with the 3. The 3 takes the edge along the top of its cell. That dot then has one line and one open edge, so the second edge follows on the next move.
Pairs at a corner Medium
Medium grids need one more idea. Two edges that meet at a dot are a pair. The pair takes one line, or it takes none, and the number or the dot is what decides which. Easy counting has already run out when this fires.
Look at the 1. Its top and its left are already crosses, so it still needs one line, and two sides are open: the bottom and the right. Both lines would give it two sides. Both crosses would leave it with none. So exactly one of those two is a line.
Those two sides meet at the dot on the 1’s bottom-right corner. The two edges that leave that dot the other way are the opposite pair. They also take exactly one line between them. One of them is already a cross, so the other is a line.
The 1 would have two lines. A 1 can take only one.
The 1 would have no line left to take. It can no longer reach its number.
Exactly one of the 1’s open sides is a line, so the pair across the dot takes one too. One of those is already a cross, so this edge is a line.
The same corner can force a pair in two other ways. A dot that already has one line can leave two edges that take exactly one line between them: a dot pair. A number can force the same thing on two of its own sides: a cell bound. Hint uses whichever of the three the grid gives it. This puzzle’s pair step is the opposite pair above.
Parity and inside/outside Hard
Hard grids still use every move above. Somewhere, counting and pairs both stop, and you need the shape of the loop: it is one closed curve.
Even cuts Hard
A straight cut across a row meets the loop an even number of times. The cut is that row’s vertical edges, including both borders. The same count runs down a column, on the horizontal edges, including the top and the bottom. When one edge of the cut is still open, the even count decides it.
Inside and outside Hard
The border of the grid is outside the loop. A line switches side: one side inside, the other outside. A cross keeps both sides the same. When you already know both sides of an edge, different sides mean a line and the same side means a cross.
The 3 on the right border already has two lines. Its cell is outside the loop, the same as the space past the border. The edge between them is empty.
Common mistakes
Almost everyone makes these at first. Each one has a simple fix.
Closing a loop too soon
Four lines around a blank cell feel tidy. If any other line is already on the board, that small loop is finished too early. Leave the closing edge empty.
Giving a number one line too many
A 3 with three lines is done. The fourth side is empty. Auto-× will cross it for you when it is on.
Making a junction
Three lines at one dot is a branch. The loop passes through a dot and leaves again: two lines, never three.
Three coral sides plus the real line along the bottom close a square in a blank cell. The line on the top border is already drawn, so the square is a second loop.
The corner 3 already has its three lines. The coral side is a fourth. With Highlight errors on, the 3 lights up as soon as that line is drawn.
The dot on the left edge already has two lines. The coral line makes three. A dot on the loop has two.
Next steps
Once the 0s and the corners feel quick, move up a level. Each one adds a new idea.
- EasyCountingZeros, corners, full numbers, dots and small loops. 5×5 is easy only. The daily is a 7×7 easy.Play Easy →
- MediumAdd corner pairsTwo edges at a dot take one line between them. 7×7 and 10×10.Play Medium →
- HardAdd parity or sidesAn even cut across a row or column, then inside and outside. 7×7 and 10×10.Play Hard →
The same ideas carry every size. A 5×5 easy is the short practice for corners. When 7×7 feels quick, try a 10×10. Want the board from this guide? Open it in the game and solve it from the start. Today’s shared puzzle is the daily 7×7 easy.