Polybius Box

Decode coordinate pairs into letters with the cipher grid — or deduce the key yourself.

Loading puzzle…

How to play

Tap a box and type its letter. Boxes (and legend cells) that share a coordinate fill together, so one deduction cascades. Decode the whole message, then press Verify.

About Polybius Box

Polybius Box is a light cipher puzzle: each coordinate pair points to a letter in the legend grid. Decode the message box by box — and in deduce-the-key mode the legend ships blank, so you reconstruct the cipher from the links between boxes.