Last reviewed 22 Sept 2026 · 5 min read
The method, whatever the type
- Write the alphabet positions of the letters of the given word and of its code, one under the other.
- Subtract: a constant difference is a shift; a difference that changes by one each letter is a growing shift; positions adding to 27 mean opposite letters.
- If the letters are the same but scrambled, it is a rearrangement.
- Apply the rule to the word asked for — never guess from the shape of the options.
; EJOTY (E=5, J=10, O=15, T=20, Y=25); opposite letters add to 27. Moving forward past Z wraps to A, so from X(24) is → C.
The six types
1. Letter shifting
Every letter moves by a fixed number. CAT → ECV is on each letter.
Shifts may also alternate ( on the first, on the second) or grow ().
2. Reverse-alphabet coding
Each letter is replaced by its opposite: A↔Z, B↔Y, and so on, the pair summing to 27. DOG → WLT, because D(4)→W(23), O(15)→L(12), G(7)→T(20).
3. Number coding
Each letter becomes a number — usually its alphabet position, sometimes its position with a shift, and sometimes the whole word becomes a single number (the sum of the positions, or the sum divided by something).
4. Coding by a rule on the word
The letters are the same but moved: reversed (NEAT → TAEN), first and last swapped, or the word split and the halves exchanged. Sometimes one letter is dropped or a letter is added.
5. Substitution coding
Words stand for other words: "if sky is called sea, sea is called river…". Answer by following the chain of names, not the real meanings.
6. Message or sentence coding
Two or three coded sentences are given, and the shared word between two sentences must correspond to the shared code. Line up the sentences, find the common word and the common code, and pair them off.
Conditional coding
Some papers give a table of letter-codes plus conditions, such as: if the first letter is a vowel, exchange the codes of the first and last letters; if the last letter is a consonant, code both first and last as the symbol for the first. Apply the conditions in the order printed, and only the first one that applies unless the paper says otherwise.