Star Battle is a logic puzzle played on a square grid split into outlined regions. You place stars so that every row, every column and every region holds the same number of stars, and no two stars touch. There is no guessing: every puzzle here has exactly one solution you can reach by reasoning.
The rules
Every row, every column and every region must contain exactly the same number of stars: one on Easy and Normal, two on Hard.
No two stars may touch, not even diagonally at a corner.
The puzzle is solved the moment every star is in place. Each puzzle has exactly one solution.
Placing stars and dots
Tap a cell to put a dot in it, meaning “no star here”. Tap again for a star, and once more to clear the cell.
Hold a cell to place a star straight away, or to remove one.
Drag across cells to dot them all at once. A drag that starts on a dot wipes dots instead.
In Settings you can make a tap place a star first, and turn on auto-dots, which dots the eight cells around every star you place.
On a keyboard, use the arrow keys to move, Space to tap, S for a star, X for a dot and Ctrl or ⌘+Z to undo.
Reading the board
The marks above each column and beside each row turn green once that line has the right number of stars, and red if it has too many. A region fades when it is complete. Any star that touches another, or crowds a row, column or region, turns red, so mistakes are easy to spot and undo.
Solving tips
Start with the smallest regions. A region only two or three cells big has very few places its star can go.
Every star rules out the eight cells around it, so dot them (or turn on auto-dots).
If a region lies entirely inside one row or column, that line’s star must be in that region, so dot the rest of the line.
Count regions against lines: if two regions fit entirely inside two rows, those rows’ stars all belong to those regions, and every other cell in those rows is empty.
On two-star puzzles, remember that any 2×2 block can hold at most one star.
Difficulty and records
Easy is a 6×6 grid with one star per row, column and region, Normal is 8×8 with one star, and Hard is 10×10 with two stars each. Every puzzle is freshly made and checked to have a single solution. The clock starts with your first mark, and your best time is kept separately for each difficulty.