Napdoku tips and solving strategy

Every board can be solved by logic. These six tricks, the same ones the in-game Sleepyhead School teaches, cover almost every move you will need.

1. The last cell

When a row, column or patch has just one free cell left, its critter sleeps right there. Start every board by looking at the smallest patches.

2. A patch in one line

When all free cells of a patch sit in one row or column, that line’s critter sleeps in the patch. Cross out the rest of the line.

3. A line inside one patch

When all free cells of a row or column lie in one patch, that patch’s critter sleeps in this line. Cross out the rest of the patch.

4. The blocking cell

If a critter in a cell would cover every free spot of some row, column or patch, nobody sleeps in that cell. Put a cross there.

5. Two patches, two rows

When two patches fit only in two rows or columns, those lines belong to them. Every other cell of those lines gets a cross.

6. Three patches, three rows

The same trick for three: three patches that fit only in three rows or columns take them whole.

Cross out around every critter

A critter rules out its row, its column, its patch and the eight cells around it. Crossing them out right away keeps the board clear, and the auto-cross setting can do it for you.