How to play Connect Pairs

Connect Pairs is played on a square grid of cells. Some cells hold a coloured dot with a number, and every number appears exactly twice. Your job is to join each pair - the two 1s, the two 2s, and so on - with a path that runs from cell to neighbouring cell, across or down, never diagonally. Paths can bend as often as they like, but they can never cross or share a cell. When you're done, the paths together must cover every cell of the board.

Puzzles like this are also known as link puzzles or path puzzles. On skill.games every puzzle is new: it is made by the game when you start, and checked before you see it. Each one has exactly one solution, and you can always reach it by reasoning, step by step. You never have to guess and hope.

Every pair has its own colour and its own number, so the game is just as readable if some colours look alike to you: the numbers on the dots tell the pairs apart.

How to play on skill.games

When you open the game, the settings popup appears. Pick a difficulty - Easy, Normal, Hard or Crazy - and how mistakes are handled (see "Mistakes" below), then press PLAY. Your choices are remembered for next time. A new puzzle takes a moment to make.

• Drawing a path: put your finger on a dot and drag through the neighbouring cells. The path follows your finger, cell by cell, in the pair's colour. When it reaches the other dot with the same number, the pair is joined and both dots get a white ring.
• Shortening a path: drag back over the path you just drew and it shrinks behind your finger.
• Carrying on: put your finger on the loose end of an unfinished path, or anywhere along it, and drag on from there. The part beyond your finger is removed.
• Clearing a path: tap one of its dots.
• Crossing another path: if you drag through a cell that another pair's path uses, that path is cut at that cell. While your finger is still down you can back off again and the other path comes back. Dots of other pairs block your path completely.
• Undo: the UNDO button takes back your last drag, as many times as you like. It's free. On a keyboard, Z does the same.
• On a computer: hold the mouse button down and drag, exactly as with a finger.

The counter at the top shows how many pairs are joined, next to the clock. The menu button in the top-left corner pauses the game and the clock, starts a new game or switches the sound on or off. The "?" button in the top-right corner opens this guide. The game is saved as you play, so if you close the page you can press CONTINUE and carry on with the same puzzle.

Rules

Paths. A path joins the two dots of one pair through neighbouring cells (across or down). It may not pass through any dot of another pair, may not cross another path, and may not use a cell twice.

Fill every cell. The puzzle is solved when every pair is joined and every cell of the board is covered by a path. This is the rule most versions of the puzzle use, and it is the one that makes the solution unique: the board here is built so that exactly one way of joining the pairs covers every cell. If you join every pair but cells are left empty, the empty cells glow red (and, on an upright screen, a line under the board reminds you to cover them) - some path has to take a longer way round.

Mistakes. In the settings you choose one of two ways to play:

• Unlimited: your paths are not checked against the answer. You can draw any path the rules allow and change it as often as you like.
• 3 lives: every step of a path is checked as you draw it. A step that isn't part of the answer is refused: the cell flashes red, the drag stops, and it costs one life. The third mistake ends the game. Undo never gives a life back.

A puzzle you leave unfinished for a new one counts as a loss in your statistics.

Solving techniques

Every puzzle here can be finished with the techniques below. The higher levels need the later ones.

• Forced moves. Every cell that isn't a dot must have a path going in and coming out, so it needs two neighbours to connect to; a dot needs one. When a cell has only as many usable neighbours as it needs, it must connect to all of them. Corner cells are the classic case: a corner with no dot has only two neighbours, so a path turns the corner through both of them.
• Dots with one way out. A dot hemmed in by the edge, other dots and finished paths has to leave through its only free neighbour.
• No loops. A path never comes back to touch itself in a closed ring: a link that would join a path to itself is out.
• Finished pairs. Once a pair is joined, its colour can't be anywhere else on the board, and the cells around it must be covered by other pairs.
• Reach. A cell can only belong to a pair whose two dots can both reach it without crossing anything. Cells in a corner that only one pair can get to belong to that pair - and a cell with only one neighbour that its pair could use can't be part of that pair at all, because a path needs a way in and a way out.
• Bottlenecks. When every route between a pair's two dots has to pass through the same cell - a gap between two finished paths, a narrow corridor along the edge - that cell belongs to that pair, whichever way the path goes in the end. The same goes for a step between two cells that every route uses.
• Fill the gaps. Because every cell must be covered, an area that only one pair can reach must be filled by that pair's path. That is usually what forces a path to wind instead of going straight.

Strategy tips

• Start at the edges and corners. Dots on the edge and in corners have the fewest ways to go, and paths along the edge rarely block anything.
• Join the short, obvious pairs first, then look at what space is left for the rest.
• Look for cells only one pair can reach. Empty pockets next to a single dot usually belong to that dot's path.
• Think about the fill rule early. If an area would be left over that no path can reach, the paths around it must change.
• Use the counter. All pairs joined but the board still glowing red means one path should take a longer route through the empty cells.
• For a fast time, draw each path in one smooth drag and let it run straight into its twin.

Difficulty levels

The difficulty sets the size of the board, the number of pairs and how far the reasoning goes. Every puzzle is checked by a solver that uses the techniques above in order, simplest first, and a puzzle belongs to a level only if it actually needs that level's technique.

• Easy: 5 by 5 with three to six pairs. Forced moves alone finish it.
• Normal: 7 by 7 with six to nine pairs. Needs reach: working out which pairs can get to a cell.
• Hard: 8 by 8 with seven to eleven pairs. Needs bottlenecks: cells every route of a pair must use.
• Crazy: 9 by 9 with eight to twelve pairs. Needs bottlenecks, usually more than once: the game makes several candidate boards and keeps the hardest.

The board sizes stop at 9 by 9 so that every cell stays easy to touch on a small phone.

The results screen shows your time, your best time at that difficulty (marked when you set a new one), the mistakes you made when playing with 3 lives, the size of the board, the number of pairs and the puzzle's code. Your statistics - wins, losses, win rate and streaks - are kept separately for each difficulty.