Hitori is a single-player logic puzzle. It’s challenging and fun but still simple and easy to learn.
How to Play Hitori
Each puzzle consists of a square grid with numbers appearing in all squares. The object is to shade squares so:
- no number appears in a column or row more than once
- shaded (colored) squares do not touch each other vertically or horizontally
- when completed, all un-shaded (white) squares create a single continuous area.
Example Hitori Puzzle (6×6)
Here we have a blank 6×6 hitori puzzle.
Remember the rules:
- Each number (1, 2, 3, 4, 5, and 6) can only appear in a column once.
- Each number (1, 2, 3, 4, 5, and 6) can only appear in a row once.
- Shaded squares cannot touch each other vertically or horizontally.
- Un-shaded squares will create a continuous area when completed.
Rule 1: Columns
The first rule is that each number (1, 2, 3 ,4, 5, and 6) can only appear in a column once.
So, I’m going to check out each column and highlight all duplicate numbers.
- Column 1 contains 2 fours.
- Column 2 contains no duplicates
- Column 3 contains 3 fours
- Column 4 contains 2 ones
- Columns 5 and 6 each contain 2 fives
Let’s look at column 3.
It has 3 fours, which means we need to shade 2 of them.
Now think of rule 3: shaded squares cannot touch each other vertically or horizontally.
2 of our fours are touching which means we cannot shade both of them. So we must shade one of these fours plus we must shade the other four (at the bottom).
We now have one square shaded.
Rule 2: Rows
The second rule is that each number (1, 2, 3 ,4, 5, and 6) can only appear in a row once.
So, I’m going to check out each row and highlight all duplicate numbers.
- Row 1 and 2 each contain 2 fives
- Row 3 contains 2 fives and 2 fours
- Row 4 doesn’t have any duplicates
- Row 5 contains 2 ones
- Row 6 contains 2 fours
Let’s take a look at rows 5 and 6.
We already know which of the fours is going to be shaded because we shaded it when we looked at the columns.
Let’s remember rule 3 again: shaded squares cannot touch each other vertically or horizontally.
This means that the first 1 in row 5 cannot be shaded because it touches our shaded 4. So we must shade the row 5 column 5 one.
Putting it Together
Now let’s take a look at rules one and two together (with our 2 shaded squares).
What you have to do now is use logic (and a bit of trial and error) to shade the remaining squares while adhering to the remaining two rules:
Rule 3: shaded squares cannot touch each other vertically or horizontally.
Rule 4: unshaded squares will create a continuous area when complete.
Let’s take a look at the cluster in the top-right corner.
Imagine that we’ve decided to shade the middle 5 (I’ve left it orange).
Rule 3 means that we can’t shade any of the horizontal or vertical boxes around it. I’ve colored those ones grey.
Because we cannot shade the one in row 2, we must shade the one in row 1 (colored dark orange).
Looks good, right?
The truth is, for this puzzle, it does work but it’s not the only possible solution. This is what makes Hitori difficult, easy, frustrating, and fun!
Can you solve the rest of this puzzle? Give it a try!
(Scroll all the way to the bottom to see the finished puzzle)