With the touching rule on (as in LinkedIn's Queens), no two stars may touch, diagonals included.
Tap a cell to mark it ×, tap again for a star, and again to clear. Drag across cells to mark several at once. Dots show cells your stars already rule out.
No puzzle needs guessing. The levels add one technique each:
Easy: last open cell in a line or region, and squeezes (a region that fits inside one row clears the rest of that row).
Medium: blockers, cells that would wipe out a whole region or line if they held a star.
Hard: pairs, two regions confined to two rows or columns.
Expert: groups of three or more.
Hint explains the next deduction and dims everything it doesn't use. Tap Do it, or press Hint again, to apply it. Small grids can't always reach the top levels, so 8×8 and up give the truest Hard and Expert puzzles.