Numberlink, in colour
Color Links is based on Numberlink, an old pencil-and-paper puzzle. You join matching numbers with lines that never cross. Here the numbers sit inside coloured dots, and each board must be filled edge to edge. Every board has exactly one solution. That matters for strategy. If you can find two ways to fill an area, at least one of them is wrong, and usually both are.
Where to begin
Not every pair is equally useful at the start. Look for the ones with the fewest possible routes.
- Pairs on the border. When both dots of a colour sit on the same edge, the line very often runs along that edge between them. Squares by the wall are hard for any other colour to reach.
- Corners. A corner square has only two neighbours. If it holds no dot, whatever line fills it must come in one side and out the other. Ask which colour can reach both neighbours.
- Short pairs. Two dots a few squares apart, with walls or other dots on either side, often have only one sensible route. Draw it early. It shrinks the space every other colour has to work with.
Leave long pairs that cross the middle of the board until last. Their route depends on everything else, and the leftover space usually shows the path for you.
Reading the empty squares
Once a few lines are down, every empty square is a small puzzle. A square with no dot needs one line coming in and the same line going out. So it needs two open neighbours that one colour can reach. If an empty square has only one open neighbour, it can only be filled by a line ending there. If no dot is there, the lines around it are wrong.
A pattern to avoid is a line that folds back on itself. Picture a line that goes along, turns, and comes straight back beside itself, leaving a strip one square wide. Or a single colour filling a whole two-by-two block. In a puzzle with one answer, those shapes almost never appear. If you can reroute a line to cover the same squares a different way, the board would have two solutions. When your line forms a tight U-bend, look again.
Here is a short example on the 5×5 Easy board. Say dot 1 sits in the top-left corner and its twin is three squares along the top edge. Any other colour reaching the squares between them would have to come down from the top wall, which is impossible. So line 1 runs straight along the top. The squares under it now have a wall above them too, and the next pair is easier to read.
Mistakes worth unlearning
- Joining every pair and stopping. The board isn't solved until every square is covered. The Filled count shows how close you are, and the game marks any empty squares left over.
- Cutting through other lines by accident. Dragging through another colour's line cuts it back. If a finished line suddenly looks shorter, that's why. Undo restores it.
- Drawing in pieces. A move counts each time you switch colours. Drawing every flow in one move, with no hints, is a perfect solve. Plan a whole line before you press its dot.
- Using Hint as a first step. Hint draws one complete flow, fixing a misplaced one first if there is one. A board finished with a hint doesn't set a best time.
Sizes and practice
Easy is a 5×5 board with five flows. Medium is 7×7 with seven, and Hard is 9×9 with nine. Easy boards teach the border and corner habits. Medium is where the fold-back check starts to pay off. On Hard, try drawing only the lines you are sure of. Then study the empty space before you touch the long pairs. Every dot also carries a number from 1 to 9, so you can tell lines apart even when two colours look alike. If you like covering every square, Number Path does the same with one long line.
