Numberlink guide
How to solve Numberlink
Numberlink looks like drawing lines until they fit. It is not: every board has exactly one solution, and two small ideas find most of it. These are the lessons from Filum, the app, played right here on the page.
The rules
- Connect every pair of ends with the same number by a single unbroken thread.
- A thread never crosses itself or another thread. Every cell carries at most one thread.
- Every single cell on the board belongs to some thread by the end — none is left empty.
What a solved board looks like
Press a numbered end and drag to extend its thread. Drag back over your own thread to shorten it.
1Drawing a thread
Put your finger on a number and drag to the matching number. Join both pairs.
2Every cell counts
Join both 1s and both 2s – so that no cell is left empty.
3Only one way
Look at the marked 1 in the bottom right. Which cell does its thread have to go into first? Drag it there.
4Tight corners
The marked corner cell has to be filled too. Which thread runs through it? Drag it in.
5A whole puzzle
Now everything together. Look for numbers and corners with only one free way first. If you get stuck, tap “Hint”.
You’re ready
- Join matching numbers – no crossing, no empty cell.
- If a thread has only one free way, it takes it.
- Tight corners tell you which thread runs through them.
That is all the theory a board needs. The big ones are the same two ideas, many moves deep.