This is an example of a completed Star Battle puzzle. The aim of this particular Star Battle puzzle is to insert one star in to every row, column, and region. Stars can't be adjacent horizontally, vertically or diagonally.

This is another example of a completed Star Battle puzzle. This puzzle is a little bigger, which means we need to insert two stars in to every row, column and region. None of the stars can be adjacent horizontally, vertically or diagonally (even those in the same row/column/region).

This is an example of a starting Star Battle puzzle. Our aim at the start of the puzzle is to pick out cells where we can't insert a star.

In this puzzle we have two regions that are a single cell in height - these are highlighted. We know that these regions must contain a star, which means that none of the other cells in these rows can contain stars. We can mark this by inserting a dot.

We now need to start looking at individual cells. If we were to insert a star in cell 'A', then that would mean that we wouldn't be able to insert a star in cells 'B', 'C', or 'D'. This would mean we would have no more free cells in that region to insert a star, i.e. a contradiction. This means that cell 'A' can't be a star, and we can insert a dot in cell 'A'.

This also means that cell 'E' must be a star - it is the only free cell left in that region. We will mark the surrounding cells with a dot since we can't have two stars adjacent horizontally, vertically or diagonally. Since we can only have one star in each row/column, we will also mark the cells in the same row and column with a dot.

Now that we have done that, we can see there are another two regions that only have a single cell available. We will insert a star in these cells, and mark the surrounding cells and the other cells in the same row/coumn with a dot.

With no more obvious cells that must contain stars, we will return to eliminating cells instead.

If we were to insert a star in to cells 'A' or 'B', this would mean that cells 'C' and 'D' can't contain stars. This would leave no more free cells in that region, i.e. a contradiction. This means we can insert a dot in cells 'A' and 'B'.

This means the only remaining available cells in this region is cell 'E', i.e. cell 'E' must contain a star.

We are now at the end of this puzzle. Cell 'A' is the only free cell in that region, i.e. cell 'A' must contain a star. This in turn means that cells 'B' and 'C' must contain the remaining stars.

This is an example of a starting grid requiring two stars in each row/column/region. These puzzles are a little harder, but the overall approach is the same. We have two regions that are only a single cell in height. We know that these regions must contain two stars, which means none of the other cells in that row can contain any stars.

In fact, for the rectangle in the middle of this puzzle, there is only one way we can insert two stars in there, i.e. in cells 'A' and 'B'.

We can also look at cell 'C'. This cell is in the middle of a small region. If we were to insert a star in here, there would be no more free cells for the other star, i.e. cell 'C' must be empty.