# Sun & Moon (Takuzu / Binairo) > Fill the grid with suns and moons: balance every row and column, never three alike. Unlimited boards, 6×6 to 10×10. Play Sun & Moon free online: a binary logic puzzle (takuzu / binairo). Balance suns and moons, follow the = and × clues. Unlimited 6×6 to 10×10 boards. - Play: https://mogame.app/en/games/sun-moon/ - Genre: Puzzle - Price: free, no ads, no sign-up, no download - Platforms: desktop, mobile (web browser) - Controls: keyboard, mouse, touch - Online leaderboard: yes - Released: 2026-10-17 - Last updated: 2026-10-29 ## How to play Sun & Moon is a binary logic puzzle, also known as takuzu or binairo. Fill every empty cell with a sun or a moon. Each row and each column must hold the same number of suns and moons, and no row or column may have three identical symbols next to each other. Some cells are joined by clues: = means the two cells hold the same symbol, × means they are different. The symbols already on the board are locked. Tap a cell to place a sun, tap again for a moon, and a third time to empty it. Broken rules light up in red right away. Every board has exactly one solution and can be solved by logic alone, without guessing. Play as many 6×6, 8×8 or 10×10 boards as you like: each size has its own leaderboard, and after every solve the next board of the same size is just one tap away. ## Controls Mouse or tap: tap a cell to cycle sun → moon → empty. Keyboard: arrow keys to move, Space or Enter to cycle, 1 or S for a sun, 2 or M for a moon, Backspace to empty a cell, Z to undo. ## Tips - Look for pairs first: two suns side by side mean the cells on both ends must be moons, and the other way round. - A gap between two equal symbols (sun, empty, sun) must be filled with the opposite one. - Count: once a row or column has its full half of suns, every other empty cell in it is a moon. - Follow the clues in chains: a known symbol next to an = or × tells you its neighbour, which often unlocks the next clue. - Every board is ranked by time, so stay calm and let the red highlights catch your mistakes. ## Frequently asked questions ### Is Sun & Moon free? Yes. Sun & Moon is completely free, runs in your browser on phone and computer, and needs no download or sign-up. ### Is this the same as takuzu or binairo? Yes. Sun & Moon is a binary puzzle in the takuzu / binairo family: two symbols, equal counts in every row and column and never three in a row. It adds = and × clues between neighbouring cells, and uses suns and moons instead of 0 and 1. ### Does every board have only one solution? Yes. Each board is built from a full solution, and a solver checks that it can be finished step by step with logic alone, which also proves the solution is unique. You never need to guess. ### How does the leaderboard work? Each board size — 6×6, 8×8 and 10×10 — has its own leaderboard ranked by solve time; lower is better. Every board is freshly generated, so you can keep playing as long as you like, and every solve time can be saved to the leaderboard for its size. ### Why do some cells turn red? Red shows a rule that is broken right now: three equal symbols in a line, too many suns or moons in a row or column, or a = / × clue that doesn't match. Fix it or undo, and the red disappears. ### Is my progress saved? Yes. Your current board and timer are saved in your browser, so you can close the page and pick up where you left off.