The rules of Bouclo
A Bouclo grid is a lattice of dots. Between two neighbouring dots you can draw a horizontal or vertical segment. Your goal is to draw a single closed loop that respects the numbers.
- One loop. All drawn segments form a single closed circuit, with no loose ends.
- No crossings, no branches. Every dot the loop touches carries exactly two segments. A dot can also stay out of the loop, with zero segments.
- Numbers count sides. A number in a cell tells you how many of its four sides belong to the loop. Cells without a number impose nothing.
The loop does not need to visit every dot. Each grid is checked by a solver before it is published, so it has a single solution you can reach without ever guessing.
The daily grid
A new grid comes out every day, identical for all players. It is taller than it is wide, so it fits whole on a phone screen. On weekdays it is of intermediate difficulty, 6 columns by 9 rows or 7 by 10. On Sundays it grows to 8 columns by 11 rows, with fewer numbers: you will need to reason about the inside and outside of the loop, or even test a hypothesis. A number is only removed if the solution stays unique without it.
How to draw the loop
The fastest way is to slide your finger from dot to dot: each step to a neighbouring dot draws the segment between them, and going back undoes what the stroke just drew. If you start the drag on a segment that is already drawn, the stroke erases instead.
Tap an edge to cycle it from empty to drawn, then to ×, then back to empty. The cross marks an edge you have ruled out: it is not checked and does not affect your score, it is a note for yourself. On a computer, a right click puts or removes a cross directly, and the keyboard works too (Enter cycles an edge, X crosses it).
The grid helps you keep track:
- a number changes look as soon as its count of drawn sides is reached, and fades once its other sides are crossed out;
- it turns red if you draw or cross too many sides;
- an open end of the line gets a ring, and a dot where three segments meet turns red;
- if the loop closes without matching the numbers, it turns red and a message tells you so;
- when the loop is right, its inside fills with colour.
Below the grid, the buttons carry French labels: Annuler (undo) and Rétablir (redo) step through your last actions (a whole stroke counts as one), Effacer clears the grid, lines and crosses alike, and Règles recalls the rules. Joker reveals an edge of the solution, locked, at the cost of a few points.
A sample grid, solved step by step
Real grids are bigger, but a 3 by 3 grid is enough to see the method. Here are the numbers of the example:
| Col. 1 | Col. 2 | Col. 3 |
|---|---|---|
| 2 | 2 | 1 |
| 2 | 2 | 1 |
| 1 | 1 | 0 |
1. The 0. The bottom-right cell is a 0: none of its four sides is drawn. All four are ruled out.
2. The 1 in a corner. The top-right 1 touches the corner of the grid. If one of its two outer sides were drawn, the corner dot, which only has those two possible segments, would need both: the cell would then have two sides, not one. Its top and right sides are ruled out.
3. Dots with a single exit. Look at the dot on the right edge, just below the middle 1. Its downward and leftward segments belong to the 0, so they are ruled out. It has only one exit left, but a dot carries zero or two segments, never one. So the right side of the middle 1 is ruled out. The dot just above now also has a single possible exit: the edge between the two right-hand 1s is ruled out in turn.
4. The right-hand 1s. Each has only one side left, its left side. Draw both: you get a vertical line of two segments separating the right column from the centre.
5. Follow the line. At the bottom, the line can neither go down nor turn right, since those edges belong to the 0: it turns left, under the centre cell. That segment satisfies the bottom 1, whose other sides are now ruled out, including the one it shares with the bottom-left 1. That 1 sits in a corner, so it has no outer side drawn either: only its top side is left, and the line carries on to the left.
6. Close the loop. At the top, the line reaches the upper edge. The segment to the right, above the corner 1, was ruled out in step 2, so it turns left. It runs along the top edge to the corner, then down the left edge until it meets the bottom segment. The loop is a square around the four 2s, and every number counts exactly its sides.
How scoring works
The game ends automatically when your loop matches the solution. Your score out of 1000 depends on time, mistakes and jokers. You can draw, erase and undo freely: a mistake is closing a loop that does not match the numbers. Each mistake costs only a small share of the score, but they add up.
Jokers are unlimited and first reveal a loop segment you have not drawn yet. Each one costs about 60 points.
What next?
After a few grids you will recognise patterns that solve at a glance: they are detailed in our Bouclo tips. Bouclo is part of our pick of daily logic games, ideal to pair with a sudoku or a Takuzu.