Cover by Ron Hale-Evans

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Hack #6. Use the Dominic System

The Dominic System, invented by World Memory Champion Dominic O'Brien, is an easier alternative to the Major System of mnemonics found in most memory books.

Dominic O'Brien, World Memory Champion, can memorize the order of a full deck of playing cards in less than a minute. To help him achieve amazing memory feats like this, he created the Dominic System of mnemonics. Some people who find the Major System [Hack #5] espoused by most memory experts to be too dry and restrictive find they can stick with the Dominic System.

In Action

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 memory palaces [Hack #3]. As many mnemonic systems do, the Dominic System requires some bootstrapping for you to reach its full potential.

You will have to spend a little time and work to memorize the structure of the system, and that might seem a little tedious. Your work will be rewarded, however, because this basic work will enable you to harness the system's full power for yourself. It's a little like starting slow on the treadmill at the gym if you want to work up to taking long hikes in the mountains.

The number-to-letter correspondences run as follows:1


You can remember the numbers 00 to 99 by linking them to famous people and actions that are characteristic of them. For example, the number 15 becomes AE. You might mentally connect the initials AE with Albert Einstein and assign writing on a blackboard as Einstein's characteristic action. Similarly, 80 = HO = Santa Claus, laughing and holding his belly (HO, HO, HO!). You can use my list2 or O'Brien's list, but the system will work best if you use the associations that are already in your own mind.3

After you have the two-digit associations firmly in your mind, you can remember four-digit numbers by combining the person associated with the first two digits and the action associated with the second two digits. Thus, 8015 can translate to HOAE, which can be broken down to HO and AE. To remember it, think of Santa Claus (HO) with Albert Einstein's action (AE): Santa Claus writing on a blackboard.

You can remember five-digit numbers by adding a symbol from the number-shape system [Hack #2] to the image, so that 80152 might be represented by Santa writing on a blackboard with a swan (2) tucked under one arm. You can remember longer sequences of numbers (such as memorizing the digits of π), or sequences of any kind, by chunking them [Hack #11] and committing them to the places of a memory journey.

Here's an example of how to memorize a 12-digit number: the month table used to calculate weekdays [Hack #43]. I will use my personal associations for the letter combinations and fill in from other sources when my own mnemonics are too idiosyncratic to make sense to most people.

First, make one long list of the month numbers. Since none of them is larger than 6, they are all one digit long, so we obtain a 12-digit number:


Next, break up this list (i.e., chunk it) into three four-digit numbers:

0336 1462 5035


Four-digit numbers are easy to memorize in the Dominic System. Besides, it's a fairly natural division; for example, all the months that end in -ber form the last group.

Now, apply the Dominic System mnemonics:

  • 0336 = OCCS = Oliver Cromwell/C.S. Lewis

  • 1462 = ADSB = Jesus (AD)/Sandra Bullock in the movie Speed

  • 5035 = EOCE = Eeyore/Clint Eastwood

Next, make an imaginary journey [Hack #3] by using the first character associated with each number performing the action associated with the second character:

Oliver Cromwell (OC) steps into the magic wardrobe and ends up in the land of Narnia (CS). He wanders through the snow until he comes to the lamppost, where he meets Jesus (AD), who leaps into a bus and starts driving away like crazy (SB). Jesus doesn't get far, however, because Eeyore (EO) appears from behind a bush and lassos him like Clint Eastwood (CE).

Did you find this little journey offensive or surreal? Strong emotional reactions help people remember things, so outlandish mental images can actually be more effective to use. Again, you should make your own list of characters for your own version of the Dominic System, and then you can tune your list to suit yourself.

How It Works

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

  • The 1 = A, 2 = B, 3 = C, and so on, Dominic System is easier to learn than the Major System's more arbitrary 1 = T/D/TH, 2 = N, 3 = M, etc. There is circumstantial evidence that the Dominic System is also faster and more powerful: Dominic O'Brien became World Memory Champion using his system, a title that includes competitions for speed in memorization.

  • The famous people of the Dominic System are combined with their characteristic actions in an easy, natural way, making numbers up to four digits long easy to memorize with a single image.

  • If you can memorize a four-digit number with the Dominic System, you can memorize 10,000 pieces of information, from 0000 to 9999 [Hack #7].

In Real Life

As my first test of the Dominic System, I used the subset of numbers from 01 to 40 to memorize the titles of a favorite series of books, the so-called Famous Forty by L. Frank Baum and his successors, set in the Marvelous Land of Oz. For example, book 23 is Jack Pumpkinhead of Oz. The number 23 corresponds to BC in my personal Dominic System, for which the person/action pair was Thor, the character from the comic strip B.C., riding his stone unicycle. Thus, the image I used to remember this book was Jack Pumpkinhead riding a stone unicycle.

Memorizing the titles of the Famous Forty took about 45 minutes, approximately a title a minute. A minute is about as long as it takes Dominic O'Brien to memorize an entire shuffled deck of cards, so at that point I had a lot of room for improvement. These days, I can memorize items several times faster than I could at the beginning—still not as fast as a World Memory Champion, but improving.

As it happened, I made a fruitful mistake with this test. I was already familiar with the more common Major System, and I thought that the Dominic System's numbers from 00 to 99 were meant to be used as mnemonic pegs or places [Hack #3], just like the numbers in the Major System. In fact, the numbers are mainly used to encode numeric information; Dominic himself would probably memorize the Famous Forty with a memory journey.

I'm glad I made my initial mistake, though, because it led me to build on the Dominic System to construct the Hotel Dominic [Hack #7], which theoretically enables you to memorize 10,000 items or more of information.

End Notes

  1. O'Brien, Dominic. 1994. How to Develop a Perfect Memory. Trafalgar Square. The canonical reference for the Dominic System, and a memory classic. Unfortunately, it is out of print in hardcopy form, and the last copy I spotted (in 2004) cost about $150. Fortunately, it is available less expensively as an e-book here: =books/how_to_develop_memory.html.

  2. A file containing my personal mnemonic pegs is available at, including my version of the Dominic System for numbers 00–99. 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 I have simply removed them in the public version and replaced them with the word PERSONAL.

  3. Blank Dominic System template for your own characters. .

See Also

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