How to solve Tango

How to solve Tango: techniques that work

Two rules generate almost every deduction. First, no three identical symbols may touch in a line: whenever you see a pair of suns side by side, both cells flanking the pair must be moons. The same applies to a gap between two identical symbols — in "sun, empty, sun" the middle cell must be a moon, or you'd create a triple.

Second, every row and column contains exactly as many suns as moons. Count as you go: once a row holds its quota of suns, the remaining cells are all moons, no further thought needed. On a 6×6 board that's three of each per line.

The = and ✕ signs chain these deductions across the board. An = sign copies whatever you learn about one cell onto its partner; an ✕ sign inverts it. Follow sign chains before touching unmarked cells — a single placement often cascades through three or four linked cells.

Common mistakes

Players often read ✕ as "anything goes". It's a hard constraint: the two cells must be different, so learning either cell instantly decides the other.

The other classic is ignoring the count rule until the end. Counting early is what turns Tango from trial-and-error into a pure logic game — many hard boards are unlocked by noticing a row already has all its suns.

From easy to hard

Easy boards give many prefilled cells and generous signs. Hard boards start nearly empty: expect to alternate between the never-three rule, the counts, and long =/✕ chains. Tango is also known as Binairo or Takuzu — the same techniques apply to any binary puzzle.