This is an example of a completed Hidoku puzzle. The puzzle starts with a partially filled grid of numbers, and your aim is to draw a single continuous line from the number 1 to the number 64 (in this case). You can move one cell in any direction, including diagonally.

This is an example of a Hidoku starting puzzle. This grid is 7x7, this means our aim is to draw a single continuous line from 1 to 7x7 = 49.

It doesn't always make sense to start solving the puzzle from the number 1, but in this case, it does. We need to insert a number 2 between the numbers 1 and 3, the only place where we can do this is in cell 'A'.

Looking in the top-left of this puzzle, we can see that the numbers 12 and 14 are next to each other, but we still need to insert a number 13 next to both. Cell 'B' is the only place where we can do this.

Cell 'C' is a little less straightforward. We know we need to insert the number 47 somewhere next to 48, and there are three possible places where we can do this. However, if 47 isn't inserted in to cell 'C', then this will leave cell 'C' as a dead-end where the path can't get back out of. This means that cell 'C' must be 47.

We can now see that there is only one possible path from 42 to 47, i.e. the path that follows through cells 'A', 'B', 'C' and 'D'. There is no other possible way for us to draw this path.

Looking at 42 from the other direction, cell 'E' is the only cell that contain 41.

Not quite as obvious, but consider the path from 28 to 32. At first, it looks like there are multiple ways to draw this path. However, if we don't insert 29 in to cell 'F', then this will leave cell 'F' as a dead-end, i.e. the path might be able to reach cell 'F' with another number, but it won't be able to get back out again.

We can now look at the bottom-left of this puzzle. We have two paths that need to cross in this situation. We need to draw a path from the 3 to the 8, and a path from 37 to 41. At first glance, it looks like there are multiple different ways to do this, but this isn't the case.

The path from 3 to 8 needs to to leave this little corner. If the path was to pass through cells 'B', 'D' and 'E', then this would leave 41 isolated with no way to insert the path from 37 to 41. This means that we can insert a 4 in to 'D', and a 5 in to 'E'. There are other options, but they all leave 14 isolated.

This means that the only possible option for the path from 37 to 41 passes through 'C', 'A' and 'B'.

We can now look at the path from 5 to 8. There are two possible ways for this path, it can pass through cells 'A' and 'B', or through cells 'B' and 'C'. Passing through 'A' and 'B' would mean that there is no possible way to get from 9 to 12, i.e. the path must pass through 'B' and 'C'. This also means that cell 'A' must be 10.

You now know all the techniques you need to finish Hidoku puzzles. This puzzle was from the 4th of November 2020, why not start with this puzzle!