The Dominic System

The Dominic System is a MemoryTechnique that made its designer, Dominic O'Brien, World Memory Champion (he can memorise the order of a full deck of playing cards in less than a minute). Some people who find the MajorSystem too dry and restrictive find they can stick with the Dominic System.


The Dominic System uses an easy-to-remember number-to-letter conversion and the initials of memorable people, as well as "journeys" that are like MemoryPalaces. The number-to-letter correspondences run as follows:

Digit Letter
1 A
2 B
3 C
4 D
5 E
6 S
7 G
8 H
9 N
0 O

The numbers 00 to 99 are remembered via famous people and actions characteristic of them. For example, the number 15 becomes AE. AE might be represented by Albert Einstein, with Einstein's characteristic action writing on a blackboard. Similarly, 80 = HO = Santa Claus, laughing and holding his belly (HO HO HO!).

Four-digit numbers can be remembered by combining the person for the first two digits with the action for the second two digits. Thus, 8015 = HOAE = Santa Claus with Albert Einstein's action = Santa Claus writing on a blackboard.

Five-digit numbers are memorised by adding a symbol from the NumberShapeSystem to the image, so that 80152 might be represented by Santa writing on a blackboard with a swan (2) tucked under one arm.

Longer sequences of numbers (e.g., PiMemorisation), or sequences of any kind, can be memorised by "chunking" them and committing them to the stages of a "journey". Journeys are the same as MemoryPalaces for most purposes, although O'Brien seems to prefer outdoor scenes, which may be why he calls them "journeys". Journeys can be indoor as well, however; one's first journey is often a tour of one's house or apartment.


The Dominic System is a combination of the innovative (easier mnemonic alphabet, using people because people are easier to remember than inanimate objects, etc.), and the tried-and-true (MemoryPalaces, which go back to classical times). It has a couple of advantages over the MajorSystem and its derivatives:

  1. The 1=A, 2=B, 3=C, etc. Dominic System is easier to learn than the Major System's more arbitrary 1=T/D/TH, 2=N, 3=M, etc., and therefore possibly faster to use. There is circumstantial evidence that the Dominic System is superior; Dominic O'Brien became World Memory Champion using his system, a title that includes competitions for speed in memorisation.
  2. There is no extra "scaffolding" on top of the MajorSystem, as there is with SemCubed; the characteristic actions are combined with the famous people in an easy, natural, integrated way, so if you can memorise 100 items with the Dominic System (00-99), you can memorise 10,000 (0000-9999).

Dry run

As a first test of the Dominic System, RonHaleEvans used it to memorise the titles of the Famous Forty, the "canonical" books set in the Land of Oz. For example, book 23 is Jack Pumpkinhead of Oz. 23 corresponds to BC in the Dominic System, for which his person/action pair was Thor, the character from the comic strip B.C., riding his stone unicycle. Thus, the image used to remember this book was Jack Pumpkinhead riding a stone unicycle.

Subtracting interruptions, memorising the titles of the Famous Forty took about 45 minutes, therefore approximately a title a minute. A minute is about as long as it takes Dominic to memorise an entire shuffled deck of cards, so this beginner has some room for improvement.

Speaking of Oz, one might also create a journey or MemoryPalace based on the palace at the center of the Emerald City.

Comparison with SemCubed

It would be interesting to compare SemCubed and the Dominic System for memorising large volumes of information in a double-blind experiment, but little enough work has been done on the MajorSystem, let alone more recent developments. Meanwhile, here's how one might memorise the PeriodicTable? example given on the SemCubed page, but in the Dominic System rather than SemCubed.

From the SemCubed page:

First of all a section of the matrix needs to be allocated to this set of data, say the locations 8001 to 8105 with 8001 being used to memorise facts about Hydrogen (atomic number 1) such as the atomic weight (1.008), the year of its discovery (1766) and its chemical symbol (H). Continuing in this way through to element Unnipentium with atomic number of 105 being placed in the matrix at location 8105.
The 8000 row of SEM cubed is the rainbow category and the range of 8000 to 8099 is the colour red so the hooks in this range should emphasise be combinations of the colour red with the the Major System images. In this way the hook for hydrogen at 8001 is 'Red Day'. Use your imagination here but I prefer to imagine the start of a new day with a huge red sun rising over the horizon, emphasise the 'redness' of the sun. I then realise that it is in fact a large hydrogen balloon not the sun. This provides my link to hydrogen.

Let's assume we want to slot the PeriodicTable? into 8001-8105 in the Dominic System as well. Starting with Hydrogen: 80, as we have already seen, is Santa Claus. 01 might be the guy on the front of the Quaker Oats package, offering a bowl of oatmeal. (01 = OA = oats.) Thus, 8001 is represented by Santa Claus offering you a bowl of oatmeal. To link in Hydrogen, imagine that the oatmeal is bubbling, and little bubbles of hydrogen gas are escaping from it and bursting into flame, or that Santa is offering you a bowl of oatmeal while leaning out of the Hindenburg. Either way, it is easy to link in the information about atomic weight, chemical symbol, date of discovery, and so on. For example, you might remember that the chemical symbol is 'H' by placing a metallic 'H' on Santa's forehead, as appears on the forehead of the "holographic" character Rimmer in the TV series Red Dwarf. The metallic 'H' reflects the flames from the exploding hydrogen bubbles.


You can also use the Dominic system web app to download a CSV file of memorable people.

An excellent reference for the Dominic System is How To Develop A Perfect Memory, Dominic O'Brien, Headline Book Publishing, 1994, ISBN 0-7472-4517-7. Unfortunately, this book is out of print, and the last copy spotted (in 2004) cost about US$150.00. How To Develop A Perfect Memory is available as a downloadable e-book from, however. Those who enjoy this book may enjoy O'Brien's other books, as well as books by Tony Buzan.

For anyone who is interested in creating their own personalised version of the Dominic System, here is a blank template in ASCII text format with the numbers 00 through 99 and the corresponding letters, ready to be filled out with well-known people. Print it out at full size and carry it around, filling in people as you think of them. When you have all your names, type them into the file, delete unnecessary whitespace, and print the file out for drill and reference. It should fit onto a single piece of paper when printed 4-up (or 2-up, double-sided).

Along these lines, Charles Cave created a small Python program to generate a template to load into Excel.

 dom = [
 (0, 'O'),
 (1, 'A'),
 (2, 'B'),
 (3, 'C'),
 (4, 'D'),
 (5, 'E'),
 (6, 'S'),
 (7, 'G'),
 (8, 'H'),
 (9, 'N')
 print "Number, Letters, Person, Action"
 for tens in dom:
    for units in dom:
        print "%d%d,%s%s,," % (tens[0], units[0], tens[1], units[1])

A file containing the mnemonic pegs used by Ron Hale-Evans is also available, including a version of the Dominic System. Use this only as an example, since many of the names in the list are idiosyncratic. Some of them refer to friends and family, and these have simply been removed in the public version and replaced with the word "PERSONAL". Here are some other examples:

Other useful resources:


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