A Polybius square replaces each letter with two numbers: its row and its column. This tool uses the 5 × 5 square below, with I and J sharing a cell. Read the row first, then the column, using numbers from 1 to 5.
The square used by this tool
| Row / column | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| 1 | A | B | C | D | E |
| 2 | F | G | H | I / J | K |
| 3 | L | M | N | O | P |
| 4 | Q | R | S | T | U |
| 5 | V | W | X | Y | Z |
Find each coordinate
Input
HELLOSettings
Fixed square; I/J merged; row then columnExpected result
23 15 31 31 34H sits in row 2, column 3, so it becomes 23. Both L letters sit in row 3, column 1 and become 31. To decode, find the letter at each pair of coordinates.
What happens to J and punctuation?
The square holds letters only. Spaces and punctuation are removed, and J becomes I; the prepared input shows you the text used. Coordinate 24 always decodes to I, so it cannot tell you whether the original message contained I or J.
Try one yourself
Encode JIG. Which part of the original spelling cannot be recovered from the tokens alone?