Free online Binary Puzzle (Takuzu, Binairo) with no ads and no sign-up. Grids from 6×6 to 14×14, a daily 10×10 puzzle, and every puzzle has exactly one solution. Hints, undo, a check button, auto-save on phone and desktop, and leaderboards for puzzles solved and the fastest 10×10 times. Fill the grid with 0s and 1s so that each row and column has as many 0s as 1s, never three of the same digit in a row, and no two rows or columns alike. Easy 6×6 and 8×8 boards can be solved with the basic moves alone; the larger boards need the counting and unique-row techniques, and the 14×14 expert board is stripped down as far as a single solution allows. Wrong entries are only counted when you press Check, and rule breaks (three in a row, too many of one digit, duplicate lines) light up in red as you play.