Binary Encoding

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Represent each letter's alphabet position as a base-2 number (0s and 1s).

Binary encoding uses only the digits 0 and 1 to represent numbers. Each position in a binary number represents a power of 2: the rightmost digit is 2^0 = 1, then 2^1 = 2, 2^2 = 4, 2^3 = 8, and so on. To encode a letter, map it to its alphabet index (A=1, B=2, ..., Z=26 or A=0, B=1, ..., Z=25 — the convention is fixed by the puzzle) and convert that index to binary. Five bits are enough to cover all 26 letters.

Letter → position → binary; e.g. C = 3 = 00011; K = 11 = 01011

• A (= 1) → 00001
• M (= 13) → 01101
• Z (= 26) → 11010
• Example: 1011₂ = 1·8 + 0·4 + 1·2 + 1·1 = 11

How to recognize it

• Only the digits 0 and 1 appear
• Each code-group is typically 5 bits (or 6 bits if 0-indexed)
• Decoding requires interpreting each group as a base-2 number

Common mistakes

• Mixing A=0 and A=1 conventions mid-decoding
• Reading bits right-to-left when the puzzle writes them left-to-right (or vice versa)
• Counting bit positions as powers of 10 instead of powers of 2

Practice guidance

Coding & Decoding