Puzzle guide
How to solve Kurotto
Kurotto is a shading puzzle with circles. Each number counts the filled cells around its circle, but not one by one: it adds up the whole groups that touch it. That one idea is what makes Kurotto different, and this guide shows you how to use it.
The rules
- Fill cells. A circle itself always stays empty.
- A circle's number is the total size of the filled groups touching it. Each group is counted once, however many of the circle's sides it touches.
- A circle without a number counts nothing: anything may touch it.
- The filled cells do not have to be connected. Get every number right and the puzzle is done.
A solved puzzle
Your first moves
- Put an X next to every 0: no filled cell may touch it.
- Remember that a group is counted whole: one filled cell next to a circle brings every cell joined to it into the count.
- Look for circles with little room around them. If all the room left is exactly enough, fill it.
- Before you fill a cell, check it does not join two groups into one that is too big.
Techniques, step by step
A 0 touches nothing
A circle with 0 may not touch any filled group. Put an X on every cell next to it. The same is true for any circle whose number is already met: every free cell that could still add to it gets an X.
Only one cell left
The 1 in the corner needs one filled cell, and its other neighbour already has an X. So the cell to its right must be filled. Whenever all the room a circle still has is exactly what it needs, fill all of it.
Too much for the number
The 1 already touches a filled cell, so its count is done. Filling the cell to the right of that filled cell would make the group two cells big, and the 1 would count 2. Filling the cell below the circle would add a second group. Both are too much, so both get an X. Checking whether a cell would push a circle past its number is the move that carries most boards.
The only way to reach the number
The 3 needs filled cells next to it, and the cell below it has an X. So its only way in is the cell to its right. Without that cell, the 3 could never reach its number, so it must be filled. On bigger boards look for these narrow spots: a cell that is the only bridge between a circle and the room it needs is filled.
Groups that join
Two separate groups near a circle can merge into one if you fill the cell between them, and then the circle counts the whole new group. That can push it past its number, but it can also be exactly what it needs. Each time you fill a cell, look at every circle its group touches and add up again.
Common mistakes
- Counting cells instead of groups. A circle adds up the size of every filled group it touches, including cells that are far away but joined to them.
- Counting a group twice. A group that touches a circle on two sides still counts once.
- Filling a circle. Circles always stay empty, even the ones without a number.
- Thinking it is Nurikabe. The filled cells do not need to be connected, and there is no rule about 2×2 blocks.
Questions and answers
Ready to play?
Count whole groups, X the cells that would overshoot, and fill the only way in. That is how every Kurotto falls into place.