Logic

Combine constraints instead of looking for one clue

Logic puzzles ask you to satisfy several rules at once. A locally plausible mark can still be wrong when it violates a second constraint elsewhere in the board.

Tree pairings and cage totals

Tents and Trees pairs a tent with a tree directly above, below, left or right. Tents cannot touch even diagonally, and row and column totals must fit. Killer Sudoku combines ordinary row, column and box uniqueness with cage sums and no repeated digit inside a cage.

Tents and Trees: Forest Camp · Killer Sudoku

Balance does not permit repeated patterns

Binario needs equal numbers of zeros and ones in every row and column, prohibits three identical symbols in succession and prohibits duplicate completed rows or columns. Check all three rules instead of stopping as soon as the symbol counts balance.

Binario: Takuzu · Compare evidence-based deduction games