Logic puzzle

Bouclo

Draw a single loop across the grid

Bouclo is a free online logic puzzle in the Slitherlink style, where you draw one single closed loop between the dots of a grid so that it matches the numbers in the cells, with a new puzzle every day.

Duration: 4–6 min
Difficulty: Medium to hard
Skill: Spatial logic
Price: Free

Play now — for free

How to play?

A Slitherlink: draw one single closed loop along the edges between the grid dots. The numbers inside the cells tell you how many of their four sides belong to the loop. Nothing else — and it is more than enough.

Click an edge between two dots to draw or erase a segment.
A cell's number says how many of its four sides are part of the loop.
The loop is single and closed, with no crossing and no branching.
Every dot the loop touches carries exactly two segments.

Why play?

One rule to remember, hours of deduction.
Trains spatial logic differently from number grids.
The most elegant puzzle in the catalogue.

Tips

Start with the 0s: none of that cell's four sides belong to the loop. They rule out several segments right away and constrain the neighbouring cells.
A 3 in a corner of the grid always has both outer sides drawn. A 1 in a corner, on the other hand, never has either of its outer sides in the loop.
Two 3s side by side force three parallel segments: the side they share and both of their opposite sides. It is often the best way into the middle of the grid.
Think in terms of dots: each one carries either zero or two segments. A dot with a single segment must continue, and a dot that already has two cannot take more.
Only draw when you are sure: every segment placed outside the solution counts as a mistake in your score, even if you erase it later. A number turning red means too many sides.

Frequently asked questions

How do you play Bouclo?

Draw a single closed loop by joining the dots of the grid with horizontal and vertical segments. Each number tells you how many of its cell's four sides belong to the loop. The loop never crosses itself and never branches. Click or drag to draw and erase segments.

Is Bouclo free to play?

Yes. Bouclo is free in your browser, on desktop or mobile, with nothing to download. You can play today's grid without an account. A free account unlocks the archive of past days, and SIWA+ (18 € a year) removes ads and adds advanced stats.

What is Slitherlink?

Slitherlink is a Japanese logic puzzle: you draw a single loop along the edges of a grid, guided by numbers that count how many sides of each cell are used. Bouclo uses exactly those rules, in a daily format with a score and a leaderboard.

Does every Bouclo puzzle have a unique solution?

Yes. Every grid is generated by an algorithm and checked by a solver before it goes live, so the solution is always unique. You can solve it by pure deduction, with no guessing. Some cells have no number, but only when that number is not needed.

Does Bouclo get harder on certain days?

Yes. On weekdays the grid is medium difficulty. On Sundays it is larger and more cells are left without a number, which calls for longer chains of deduction. If you get stuck, the joker reveals one correct segment, at the cost of a few points.