The Japanese counting system, like the Chinese one on which it is based, uses groups of four zeros rather than three as the basic unit for counting large numbers. The primitives from ten onward therefore proceed thus:

10 10
102 hyaku 100
103 sen 1000
104 man 10,000
108 oku 100,000,000
1012 chō 10,000,000,000,000,000

At the same time, however, they are written with commas after every three digits, just to confuse matters further. (I am, however, led to believe that the comma was used after four digits as recently as fifty years ago.)

The second problem comes in the fact that the “big” unit of currency, corresponding closely to a hundred US dollars or euros, is 10,000 yen, or ichi man en.

As a result of this, most Western expatriates in Japan, even when speaking in English—and even those who speak no Japanese—use man as a counter for money. “My apartment costs seven man a month.” “The Shinkansen to Tokyo costs 1.3 man each way.”

I heard this kind of conversation frequently among gaijin in Japan, and it wasn’t affected or strange—it was the most reasonable method of dealing with the mathematical speed bump that converting between two different counting systems would have entailed.

Now, I had dinner with a group of mostly Japanese yesterday evening, and much of the conversation took place in Japanese. I was intrigued to overhear two expatriate Japanese next to me discussing the price of houses in Brussels and Amsterdam, and dropping English numbers like “three hundred thousand” into the middle of the conversation.

There was a pleasing symmetry about it.