🔤 Letter Coding — Basics
Master the fundamentals of letter-based coding-decoding including EJOTY, CFILORUX, place values, reverse letters, and core pattern types for banking exams
Letter Coding — Basics
Coding-Decoding is one of the most scoring topics in the Reasoning section of banking exams. It appears in IBPS PO/Clerk, SBI PO/Clerk, RRB PO/Clerk, and NABARD exams and carries 3-5 marks in Prelims. The questions test your ability to detect hidden patterns and apply them to new inputs.
In this lesson, we cover the foundation — letter-based coding, quick-reference systems, and the four core pattern types you will encounter repeatedly.
What is Coding-Decoding?
In coding-decoding, a word (the original) is converted into another word or code (the coded form) using a specific rule or pattern. Your job is to:
- Detect the pattern from the given example(s)
- Apply that pattern to a new word to find its code (or decode a given code)
The pattern might involve shifting letters forward or backward, reversing them, converting to numbers, or combining multiple operations.
Types of Coding-Decoding
Here is an overview of all the types you will encounter across this course:
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Letter Coding — Basics
Coding-Decoding is one of the most scoring topics in the Reasoning section of banking exams. It appears in IBPS PO/Clerk, SBI PO/Clerk, RRB PO/Clerk, and NABARD exams and carries 3-5 marks in Prelims. The questions test your ability to detect hidden patterns and apply them to new inputs.
In this lesson, we cover the foundation — letter-based coding, quick-reference systems, and the four core pattern types you will encounter repeatedly.
What is Coding-Decoding?
In coding-decoding, a word (the original) is converted into another word or code (the coded form) using a specific rule or pattern. Your job is to:
- Detect the pattern from the given example(s)
- Apply that pattern to a new word to find its code (or decode a given code)
The pattern might involve shifting letters forward or backward, reversing them, converting to numbers, or combining multiple operations.
Types of Coding-Decoding
Here is an overview of all the types you will encounter across this course:
| Type | What Changes | Difficulty |
|---|---|---|
| Letter Coding | Letters shifted/reversed | Easy-Moderate |
| Number Coding | Words coded as numbers | Moderate |
| Paragraph/Chinese Coding | Sentences coded as word groups | Moderate |
| Mixed Coding | Letter + Number + Symbol combined | Moderate-Hard |
| Conditional Coding | Rules with conditions (if vowel, then...) | Hard |
| Matrix Coding | Row-column grid selection | Moderate |
| Binary Coding | 0s and 1s representation | Moderate |
| Symbol/Clock Coding | Symbols or clock positions | Hard |
This lesson focuses on Letter Coding, the most fundamental type.
Quick-Reference Systems
Before solving any coding problem, you need to know the position of every letter instantly. These two systems let you do that in seconds.
The EJOTY System
EJOTY gives you five anchor points — every 5th letter of the alphabet:
| Letter | E | J | O | T | Y |
|---|---|---|---|---|---|
| Position | 5 | 10 | 15 | 20 | 25 |
How to use EJOTY: To find any letter's position, locate the nearest EJOTY anchor and count forward or backward.
- G = E(5) + 2 = 7
- M = J(10) + 3 = 13 (or O(15) - 2 = 13)
- R = T(20) - 2 = 18
- W = Y(25) - 2 = 23
With practice, you should find any letter's position in under 2 seconds.
The CFILORUX System
CFILORUX gives you eight anchor points — every 3rd letter:
| Letter | C | F | I | L | O | R | U | X |
|---|---|---|---|---|---|---|---|---|
| Position | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 |
This is useful when the gap between EJOTY anchors feels too wide. For example:
- D = C(3) + 1 = 4
- H = I(9) - 1 = 8
- Q = R(18) - 1 = 17
- V = U(21) + 1 = 22
Tip: Memorize EJOTY first — it covers 90% of cases. Use CFILORUX as a backup for tricky letters like D, H, N, Q, V.
Complete Place Value Table
Every letter has a fixed place value (position number). This table is the foundation of all coding-decoding:
| A | B | C | D | E | F | G | H | I | J | K | L | M |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 |
Reverse Letter Concept
Each letter has a reverse counterpart. The 1st letter pairs with the 26th, the 2nd with the 25th, and so on:
| Original | A | B | C | D | E | F | G | H | I | J | K | L | M |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Reverse | Z | Y | X | W | V | U | T | S | R | Q | P | O | N |
| Original | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Reverse | M | L | K | J | I | H | G | F | E | D | C | B | A |
Quick formula: Reverse of letter at position N = letter at position 27 - N
- Reverse of C (3) = 27 - 3 = 24 = X
- Reverse of G (7) = 27 - 7 = 20 = T
- Reverse of R (18) = 27 - 18 = 9 = I
The Letter Coding Approach
For any letter coding question, follow this method:
Step 1: Convert both the original word and the coded word into their Numerical Letter (place value) forms.
Step 2: Find the difference between each pair (coded position - original position).
Step 3: Identify the pattern in the differences.
Step 4: Apply that same pattern to the answer word.
Four Main Pattern Types
| Pattern | Description | Example | Logic |
|---|---|---|---|
| +N (uniform) | Each letter shifted forward by N | MARKET coded as OCTMGV | Each letter +2 |
| -N (uniform) | Each letter shifted backward by N | CONSTANT coded as BNMRSZMS | Each letter -1 |
| Alternating +/- | Different shift for odd/even positions | BOXER coded as AQWGQ | -1, +2, -1, +2, -1 |
| Reverse | Each letter replaced by its reverse | GIVE coded as TREV | G(7)->T(20), I(9)->R(18)... |
| Reverse +/- N | Reverse first, then shift | Two-step operation | Reverse then adjust |
Wrap-Around Rule
The alphabet is circular. When shifting takes you past Z or before A:
- Z + 1 = A (after Z, wrap back to the start)
- A - 1 = Z (before A, wrap to the end)
- Y + 3 = B (Y -> Z -> A -> B)
Think of the 26 letters arranged in a circle. Shifting always continues around the loop.
Solved Example 1: Uniform -1 Pattern
Question: In a certain code language, CONSTANT is coded as BNMRSZMS. How is TALENT coded in that language?
(1) RZKDMS (2) SZKDLS (3) SZKDMS (4) RZKDLS
Working:
Convert CONSTANT and BNMRSZMS to place values and find the difference:
| Original | C | O | N | S | T | A | N | T |
|---|---|---|---|---|---|---|---|---|
| Position | 3 | 15 | 14 | 19 | 20 | 1 | 14 | 20 |
| Coded | B | N | M | R | S | Z | M | S |
| Code Pos | 2 | 14 | 13 | 18 | 19 | 26 | 13 | 19 |
| Diff | -1 | -1 | -1 | -1 | -1 | -1 | -1 | -1 |
Pattern: Each letter is shifted -1 (one position backward).
Note: A - 1 = Z (wrap-around). So A(1) - 1 = Z(26).
Now apply to TALENT:
| Original | T | A | L | E | N | T |
|---|---|---|---|---|---|---|
| Position | 20 | 1 | 12 | 5 | 14 | 20 |
| -1 | 19 | 26 | 11 | 4 | 13 | 19 |
| Coded | S | Z | K | D | M | S |
TALENT = SZKDMS
Answer: (3) SZKDMS
Solved Example 2: Alternating Pattern
Question: In a certain code language, BOXER is coded as AQWGQ. How is VISIT coded in that language?
(1) UJRKS (2) UKRKS (3) UKRIS (4) WJRKS
Working:
| Original | B | O | X | E | R |
|---|---|---|---|---|---|
| Position | 2 | 15 | 24 | 5 | 18 |
| Coded | A | Q | W | G | Q |
| Code Pos | 1 | 17 | 23 | 7 | 17 |
| Diff | -1 | +2 | -1 | +2 | -1 |
Pattern: Alternating -1, +2, -1, +2, -1 (odd positions get -1, even positions get +2).
Apply to VISIT:
| Original | V | I | S | I | T |
|---|---|---|---|---|---|
| Position | 22 | 9 | 19 | 9 | 20 |
| Pattern | -1 | +2 | -1 | +2 | -1 |
| Result | 21 | 11 | 18 | 11 | 19 |
| Coded | U | K | R | K | S |
VISIT = UKRKS
Answer: (2) UKRKS
Solved Example 3: Vowel/Consonant Pattern
Question: POSTER is coded as QNTUDS. If the same logic applies, what is the code for CANDLE?
(1) DZMCKE (2) DBMCKE (3) DBOCKE (4) DZOEMD
Working:
First, identify vowels and consonants in POSTER:
| Letter | P | O | S | T | E | R |
|---|---|---|---|---|---|---|
| Type | C | V | C | C | V | C |
| Position | 16 | 15 | 19 | 20 | 5 | 18 |
| Code | Q | N | T | U | D | S |
| Code Pos | 17 | 14 | 20 | 21 | 4 | 19 |
| Diff | +1 | -1 | +1 | +1 | -1 | +1 |
Pattern: Consonants get +1, Vowels get -1.
Apply to CANDLE:
| Letter | C | A | N | D | L | E |
|---|---|---|---|---|---|---|
| Type | C | V | C | C | C | V |
| Position | 3 | 1 | 14 | 4 | 12 | 5 |
| Pattern | +1 | -1 | +1 | +1 | +1 | -1 |
| Result | 4 | 26 | 15 | 5 | 13 | 4 |
| Coded | D | Z | O | E | M | D |
Note: A(1) - 1 = Z(26) using wrap-around.
CANDLE = DZOEMD
Answer: (4) DZOEMD
Solved Example 4: Uniform +2 Pattern
Question: In a certain code language, MARKET is coded as OCTMGV. How is BANKER coded in that language?
(1) DCPMGT (2) DCMPGT (3) DCPNGT (4) DCMPHT
Working:
| Original | M | A | R | K | E | T |
|---|---|---|---|---|---|---|
| Position | 13 | 1 | 18 | 11 | 5 | 20 |
| Coded | O | C | T | M | G | V |
| Code Pos | 15 | 3 | 20 | 13 | 7 | 22 |
| Diff | +2 | +2 | +2 | +2 | +2 | +2 |
Pattern: Each letter shifted +2 uniformly.
Apply to BANKER:
| Original | B | A | N | K | E | R |
|---|---|---|---|---|---|---|
| Position | 2 | 1 | 14 | 11 | 5 | 18 |
| +2 | 4 | 3 | 16 | 13 | 7 | 20 |
| Coded | D | C | P | M | G | T |
BANKER = DCPMGT
Answer: (1) DCPMGT
Solved Example 5: Alternating +1/-1 Pattern
Question: In a certain code language, EVENING is coded as FUFMJMH. How is MORNING coded?
(1) NLSOJOH (2) NNSMJMH (3) NPSOJOH (4) NPSNJNI
Working:
| Original | E | V | E | N | I | N | G |
|---|---|---|---|---|---|---|---|
| Position | 5 | 22 | 5 | 14 | 9 | 14 | 7 |
| Coded | F | U | F | M | J | M | H |
| Code Pos | 6 | 21 | 6 | 13 | 10 | 13 | 8 |
| Diff | +1 | -1 | +1 | -1 | +1 | -1 | +1 |
Pattern: Alternating +1, -1, +1, -1, +1, -1, +1 (odd positions +1, even positions -1).
Apply to MORNING:
| Original | M | O | R | N | I | N | G |
|---|---|---|---|---|---|---|---|
| Position | 13 | 15 | 18 | 14 | 9 | 14 | 7 |
| Pattern | +1 | -1 | +1 | -1 | +1 | -1 | +1 |
| Result | 14 | 14 | 19 | 13 | 10 | 13 | 8 |
| Coded | N | N | S | M | J | M | H |
MORNING = NNSMJMH
Answer: (2) NNSMJMH
Solved Example 6: Alternating +1/-1 Pattern (5-letter word)
Question: In a certain code language, POWER is coded as QNXDS. How is TIGER coded?
(1) UHHDS (2) UJFDS (3) UJHDS (4) UJHFS
Working:
| Original | P | O | W | E | R |
|---|---|---|---|---|---|
| Position | 16 | 15 | 23 | 5 | 18 |
| Coded | Q | N | X | D | S |
| Code Pos | 17 | 14 | 24 | 4 | 19 |
| Diff | +1 | -1 | +1 | -1 | +1 |
Pattern: Alternating +1, -1, +1, -1, +1 (odd positions +1, even positions -1).
Apply to TIGER:
| Original | T | I | G | E | R |
|---|---|---|---|---|---|
| Position | 20 | 9 | 7 | 5 | 18 |
| Pattern | +1 | -1 | +1 | -1 | +1 |
| Result | 21 | 8 | 8 | 4 | 19 |
| Coded | U | H | H | D | S |
TIGER = UHHDS
Answer: (1) UHHDS
Pattern Detection Summary Table
When you see a letter coding question, convert to numbers and check these patterns in this order (most common first):
| Check Order | Pattern | How to Detect |
|---|---|---|
| 1st | Uniform +N or -N | All differences are the same number |
| 2nd | Alternating +a, -b | Differences alternate between two values |
| 3rd | Vowel/Consonant rule | Vowels get one shift, consonants get another |
| 4th | Position-based | Shift depends on position (1st letter +1, 2nd +2, etc.) |
| 5th | Reverse | Coded letters are reverse equivalents |
| 6th | Reverse +/- N | After reversing, a uniform shift is applied |
Speed Tips for Exam
- Memorize EJOTY — this single trick saves 20-30 seconds per question by letting you instantly find any letter's position
- Work with differences, not letters — always convert to numbers first, then find the pattern in the differences
- Check both ends first — compare the first and last letter pair. If both show the same difference, it is likely a uniform shift
- Odd/Even awareness — if differences alternate, check if odd-positioned letters get one treatment and even-positioned letters get another
- Wrap-around alert — if your shift takes a letter past Z (e.g., Y+3), remember Z+1=A. Similarly, if you go below A, wrap to Z
Common Traps
- Forgetting wrap-around: A - 1 is Z (not 0). Y + 3 is B (not some invalid letter). Always apply mod-26 arithmetic
- Miscounting position: G is 7, not 6. Double-check using EJOTY (G = E+2 = 5+2 = 7)
- Assuming uniform shift too quickly: Check ALL letter pairs, not just the first two. The pattern might be alternating
- Ignoring vowel/consonant distinction: If a uniform pattern does not work, check if vowels and consonants are treated differently
- Mixing up +N and -N: If the coded letter comes BEFORE the original in the alphabet, the shift is negative. If AFTER, it is positive