In Japanese, telephone numbers can invariably be made into mnemonic phrases based on various pronunciations of their component digits.

There are two Japanese counting systems: the Sino-Japanese system (ichi, ni, san, ...) and the native Japanese system (hī, fū, mī, ...). In addition, there is a widespread, if sketchy, understanding of English numbers. This range of systems, along with variation within those systems, gives plenty of scope for forming a memorable expression for almost any number. In the following explanations, I have indicated the use of Sino-Japanese numbers with [S] and of native Japanese numbers with [N]. I hope that English derivations will be obvious.

One of my favourite examples is 0120-5-109-2-3, used by Berlitz, a chain of language schools:

  • 0120 is a free dial prefix.
  • 5 → go [S].
  • 109 is two numbers: 10 = tō [N], and 9 = ku [S]. Together, they make the English word “talk” (that is, they do the way the Japanese pronounce it).
  • 2 → “two”.
  • 3 → mi.

The whole number can therefore be read as “Go! Talk to me!”—appropriate for an English language school. In fact, 109 for “talk” is used frequently on advertising.

Another good example is JR West’s (a railway operator) reservations line, 0088-24-5489:

  • 0088 is another free dial prefix.
  • 2 → ni [S].
  • 4 → shi [S].
  • 5 → go [S] again.
  • 4 → yo [N] this time.
  • 8 → ya [N].
  • 9 → ku [S] once more.

24 is thus nishi (西), meaning “west”. The remaining four digits make goyoyaku (ご予約) which is the word for “reservation” (with a polite prefix).

These aides memoire can be found in small kana over the top of telephone numbers on many billboards in Japan.

However, although telephone numbers are the context in which I’ve seen these mnemonics used most often, they are used in other situations as well. For example, schoolchildren find it easy to remember 1492 (the year in which Columbus “discovered” the New World, although I shall leave aside any snarks about the bogosity of the concept of “discovering” an already populated continent for now) with the expression “イヨ！クニが見えた！” (Iyo! Kuni ga mieta, or “Hey, I saw land!”):

  • 1 → i [S]
  • 4 → yo [N]
  • 9 → ku [S]
  • 2 → ni [S]

I’m sure that, had I known Japanese when I was studying History at school, I’d have been able to waste a lot less time on rote memorisation of the dates of various events—all of which, naturally, I have now forgotten.

One of the most creative mnemonics is, perhaps, the extended version of the mathematical value π, in which the digits are made to tell a story. Unfortunately, I don’t know it…