Score
0
Time
180s
Best
-
Number chain puzzle in the Hidato style. Fill the grid with 1 to N so every number touches the next one — across, down or diagonally. Solve as many grids as you can in 180 seconds.
Every cell of the grid gets one number from 1 up to the number of cells. Consecutive numbers must touch: 7 has to sit next to 8, horizontally, vertically or diagonally. Gold numbers are givens that show parts of the chain.
The line above the grid shows the next number to place — the smallest number not yet on the board. Tap an empty cell to put it there. The cell holding the previous number is outlined, and the empty cells around it are shaded so you can see where the chain can go. Tap one of your own numbers to remove it.
If two consecutive numbers end up apart, both turn red. Complete the chain to score a point; a new grid appears at once. The first two grids are 5×5, then 6×6 with fewer givens as you score. Solve as many as you can before the 180 seconds run out.
Count the gap between givens. If 9 and 12 are both on the board, the two numbers between them must fit in a path of exactly three steps from 9's cell to 12's cell. When they are exactly three cells apart, every step has to move one cell closer, so the path stays inside a narrow band; when they are closer the chain can wander, but often only one route avoids trapping another region.
Watch the corners and edges. A corner cell has only three neighbours, so whatever number goes there needs both its predecessor and successor among those three cells. Late in a grid, an empty corner is often the tightest spot on the board, and it should be filled before the chain wanders off elsewhere.
Never strand a cell. Before placing a number, check that every empty cell still has at least one route back into the chain. An empty cell surrounded by filled cells whose neighbours do not match is a dead end, and the only fix is to pull the chain back to before you cut it off.
Hidato was invented by the Israeli mathematician Gyora Benedek; its orthogonal-only cousin is Numbrix. Diagonal moves make the chain far more flexible, which is exactly why the givens matter so much — every grid here is generated to have one solution only, so if your chain disagrees with a given, the mistake is earlier than you think.