Dominic System Endoder & Decoder

Letter-to-Number Mapping
0 = O
1 = A
2 = B
3 = C
4 = D
5 = E
6 = S
7 = G
8 = H
9 = N
Letters not in this list (F, I, J, K, L, M, P, Q, R, T, U, V, W, X, Y, Z) are ignored
Results update automatically as you type

Highlighted letters have numeric values. Hover over them to see the digit.

What is the Dominic System?

The Dominic System is a mnemonic technique for remembering numbers, created by Dominic O'Brien, an eight-time World Memory Champion. It differs from the Major System by using a simpler letter-based approach that pairs well with the person-action mnemonic method.

About Dominic O'Brien

Dominic O'Brien is one of the most successful competitive memorizers in history. Despite struggling with attention difficulties in school, he developed his own memory techniques and went on to win the World Memory Championship eight times between 1991 and 2001.

He has authored several books on memory improvement, including "How to Develop a Brilliant Memory Week by Week" and "You Can Have an Amazing Memory."

The Letter-Number Mapping

The Dominic System uses a straightforward mapping based on the shapes and sounds of letters and numbers:

Digit Letter Memory Aid
0 O O looks like 0
1 A A is the 1st letter of the alphabet
2 B B is the 2nd letter of the alphabet
3 C C is the 3rd letter of the alphabet
4 D D is the 4th letter of the alphabet
5 E E is the 5th letter of the alphabet
6 S S looks like 6 / Six starts with S
7 G G looks like 7 rotated
8 H H has 8 angles / Eight sounds like H
9 N N is the 9th sound / Nine starts with N

How It Works: The Person-Action Method

The Dominic System is typically used with the Person-Action (PA) method. Each two-digit number becomes a pair of letters representing a person's initials:

  1. Convert the two digits to their letters (e.g., 15 → AE)
  2. Think of a famous person with those initials (AE → Albert Einstein)
  3. Associate that person with a characteristic action (Einstein → writing equations)
  4. To remember 15, visualize Einstein writing equations

Example: Creating a Character List

Number Letters Person Example Action
15 AE Albert Einstein Writing on a blackboard
23 BC Bill Clinton Playing saxophone
68 SH Sherlock Holmes Looking through magnifying glass
90 NO Noel Gallagher Playing guitar

Combining Numbers

For longer numbers, you combine people and actions. For a 4-digit number like 1568:

  1. 15 = Albert Einstein (person)
  2. 68 = Sherlock Holmes' action (looking through magnifying glass)
  3. Combine: Einstein looking through a magnifying glass

This "person-action" combination creates vivid, memorable images that are much easier to recall than abstract numbers.

Dominic System vs Major System

Aspect Dominic System Major System
Mapping basis Alphabetic position / visual similarity Phonetic sounds
Letters used Only 10 letters Most consonants
Primary use Person-action method Creating word pegs
Flexibility More rigid (fixed letters) More flexible (many words per number)
Learning curve Easier to learn initially Takes longer to master

Building Your Character List

To use the Dominic System effectively, you need to create a list of 100 characters (00-99). Here are some tips:

  • Use people you know well - celebrities, friends, family, fictional characters
  • Make actions distinctive - each person should have a unique, vivid action
  • Be consistent - always use the same person for the same number
  • Fill gaps creatively - if no famous person fits, create a fictional one or use sound-alikes

Practical Applications

  • Remembering dates: Link historical events to person-action combinations
  • Card memorization: Assign a person to each card in a deck
  • Number sequences: Create memorable stories with multiple characters
  • Binary data: Can be adapted for computer science applications