How to play Links

Links is a puzzle about sharing space. Every pair of numbers wants a line between them, every cell wants a line through it, and no two lines can cross. Those three demands leave exactly one way to draw the board.

The rules

• Each number on the grid appears exactly twice. Join every pair with a single line.
• Lines run from cell to cell, across or up and down — never diagonally — and turn wherever they like.
• Lines never cross or branch, and a line can't pass through a number that isn't its own.
• When you're done, every cell is part of a line.

Every puzzle has exactly one solution, and you can always reach it by reasoning. The last rule does most of the work: with no cell left empty, a line can't simply take the shortest way.

Your first moves

Start in the corners. A corner cell has only two neighbours, and any cell without a number needs a line going in and out — so an empty corner uses both of its neighbours.

The same reasoning works anywhere once a cell is squeezed. Each line you draw takes cells away from its neighbours, and a cell left with just two ways out has to use them both.

A number works the same way with one: it's the end of its line, so a number with only one free neighbour sends its line there. The strategy guide covers the reasoning that takes you further.

Playing on this site

• Drag to draw a line: from a number, from the end of a line, or anywhere you know a line must go. Pieces join up as they meet.
• Drag back over what you just drew to take it back. A drag that starts along an existing line erases it.
• Long-press (or right-click) a cell to clear every line through it.
• A number turns solid once its line reaches its partner. A line that joins two different numbers, or closes into a loop, is marked in red straight away. Check shows any link that disagrees with the solution, but only when you ask.
• Hint names the next step and outlines the cells it settles. One hint per puzzle is free; after that there's a one-minute wait between hints.

Keyboard

• Arrow keys move; Shift + arrow draws a link from the cell you're on, or erases it; 0 clears the cell.
• Z undoes, Y redoes, H asks for a hint.

Sizes and the daily puzzle

• Easy: 6×6.
• Medium: 8×8.
• Hard: 10×10.

Each day's first puzzle is the same for everyone, and they follow the week from Monday's gentlest to Saturday's toughest, with Sunday the next toughest. After it, Next puzzle gives you as many more as you like.