Hitori
Love puzzles, hate maths? Then Hitori is just the ticket. Because although this bamboozling logic puzzle involves numbers, there's absolutely no arithmetic involved. In fact the squares on a Hitori grid could, in theory, contain anything Ð from fruit to famous faces. But for now, let's stick with numbers.
How to...
The idea is to shade out boxes within the grid so that there are no duplicate numbers in any row or column. Sounds easy, but here's the twist: none of the shaded boxes can be adjacent, either vertically or horizontally. What's more, each box left unshaded must be attached to at least one other unshaded box (vertically or horizontally).
Starting any Hitori involves scanning the grid for your first shading square. This can be done in countless ways but the easiest to spot is the three-in-a- row/column.
Click on a square to shade it. To correct a square and un-shade it, click on it again.
Example 1
You know you can't have duplicate numbers in any row or column, so if you spot the same number three times in a row or column, two of them must be shaded. If the duplicate numbers are next to each other you have to shade the squares on either end because you know that the shaded boxes can't be adjacent. In this example two of the duplicate digits are adjacent but one of them is further down the row. You can't shade out the adjacent squares, so it has to be the one that's on its own.
Example 2
Once you've shaded your first squares, you should follow the rule that says the shaded squares cannot be adjacent. In this example the numbers (circled) next to the shaded 6 can't be shaded, so it has to be the duplicate numbers in red that are shaded out.
Example 3
Remember the rule stating that each unshaded box must be attached to at least one other unshaded box? Well that's the key to successfully completing a Hitori. In this example there are two 4s in the same row. We know that one must be shaded out. But which one? Well the 2 is a definite blank square and because it is in the corner it can only connect to one other square (one of the 4s). Therefore it must be the other 4 that needs to be shaded out
