How to play Ursa Stars

In Ursa Stars, your goal is to place stars on a grid divided into regions, with the right number in every row, column and region, and no two touching.

The rules

Every row, column and region must contain the same number of stars: one in 6×6 and 8×8 grids, and two in 10×10 grids.
Stars cannot touch, not even diagonally.
Every puzzle has exactly one solution, which can always be found by logic alone, without guessing.

Stars and dots

Each tap on a cell cycles through its states: empty, dot, star, and back to empty. A dot marks a cell where you know there can't be a star. Dragging from an empty cell places dots along the path, and dragging from a dotted cell removes them. On a computer, right-click to place or remove a star directly. Dots are just notes to keep track of your deductions: the puzzle is solved once all the stars are in place.

How to solve it

Around a star, none of the eight neighbouring cells can hold another star: mark them all with dots.
Once a row, column or region is complete, it takes no more stars: its remaining cells must be empty.
The last remaining cells: when a row, column or region has as many free cells left as stars still needed, all of them must be stars.

Trapped regions: if the stars of two regions can only fit in two rows, those rows must hold all their stars, leaving no room for any others: the remaining cells in those rows must be empty. The same logic applies to any number of regions, and to columns.

The two highlighted regions can only place their stars in rows 1 and 2. Since each region needs one star, those are the two stars of rows 1 and 2, and every other cell in those rows must be empty (×).

The impossible star: if placing a star in a cell would leave another row, column or region without enough room for its stars, that cell cannot hold a star and must be left empty.

A star in the marked cell would touch three cells of the highlighted region and occupy the column of the other two, leaving the region with nowhere to place its star. So the marked cell must be empty (×).

The Hint button uses these techniques, starting with the simplest and moving on to the more advanced. It first shows you where to look, and only then what you can deduce.