How to Play Number Chain

Learn the rules of Number Chain, the number path puzzle: fill the grid so the numbers run from 1 to the end, each touching the next. Controls, difficulties and solving tips.

Play Number Chain

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Number Chain is a path puzzle on a square grid. Some numbers are given; your job is to fill every empty square so the numbers run in order from 1 to the last one, with each number touching the next.

The rules

Every square holds one number, from 1 up to the number of squares (25, 49 or 81). Each number must touch the next one: beside it, above, below or diagonally. So the numbers trace one unbroken path that visits every square once.

Every puzzle has exactly one solution, so you can always work it out by reasoning, with no guessing.

How to place numbers

Tap a number to select it. The empty squares touching it light up, each showing the number that would go there.
Tap a lit square to place that number. The selection moves on, so you can keep tapping to lay a run.
Or drag from a number through the squares. Each one you cross gets the next number, and dragging back takes the last one off.
Use Up and Down to choose whether you place the next number or the one before it.
Erase removes the selected number, Clear removes all of yours, and Undo takes back your last move.

Reading the board

Dark numbers are the given clues and can’t be changed.
A line joins each pair of consecutive numbers that touch, so finished stretches stand out.
A number turns red when the number before or after it is on the board but doesn’t touch it.

Difficulty levels

Easy: a 5×5 grid, numbers 1 to 25, with plenty of clues.
Normal: a 7×7 grid, numbers 1 to 49.
Hard: a 9×9 grid, numbers 1 to 81, with fewer clues and longer gaps.
Your best time is kept separately for each level.

Solving tips

Start with short gaps: if 12 and 14 are given, 13 must touch both, and often only one square does.
Count distance: a number k steps after a clue can be at most k squares away from it, which rules out far squares.
Look for squares with few empty neighbours, such as corners and edges, which have to be the end of a stretch or sit between two clues.
Work backwards from a clue by switching to Down when the squares before it are easier to place.

Learn more

How to play Number Chain: the full rules All guides