Hard Slitherlink
Hard Slitherlink puzzles are 10×10 and need deeper reading: track how many lines can enter each corner of a number, and colour cells as inside or outside the loop.
Hard puzzles need at least one of these techniques, and may use any easier one:
- Corner flow
- Track how many lines can enter each corner of the highlighted cells; passed across dots and numbers, it settles the marked edge.
- Inside and outside
- Every cell is inside or outside the loop: a line separates the two sides and a cross joins them.
How to play
Slitherlink is a loop puzzle on a grid of dots. Draw lines between neighbouring dots to make one single closed loop. A number in a cell tells how many of its four sides the loop uses; cells without a number can have any count.
Every Slitherlink here has exactly one solution and can be solved by logic alone. The grid grows from 5×5 at Easy to 10×10, and the level is set by the hardest technique the puzzle needs.
- Draw one continuous loop along the grid lines, with no branches and no crossings.
- A number counts how many of its cell's sides are part of the loop.
- The loop never touches itself: every dot has two lines or none.
Playing on this site
- Tap an edge to draw a line, tap again to cross it out, and once more to clear it.
- Drag from dot to dot to draw several lines at once; a drag that starts on a line erases instead.
- A number fades once it has all its lines.
- Crosses are only a helper: the puzzle is solved as soon as the loop is complete.
- Hint points out wrong lines and crosses first, then names the next technique and highlights the edges it decides.
- Your puzzle is saved in this browser, so you can come back to it later.