One way to start a conversation with a Tokyo taxi driver is to do what I did and remark, "あっ、大日本帝国さんですね" ("Ah, Dainippon Teikoku-san desu ne," "Oh, I see that you are the 'Empire of Japan' company").

That's only if you're riding in a taxi operated by one of four long-established companies — 大和 (Daiwa), 日本交通 (Nihon Kotsu), 帝都 (Teito) and 国際 (Kokusai). Back in the 1940s, they had exclusive contracts to transport members of Japan's military. This enabled them to obtain extra gasoline rations, and someone figured out that the first characters used to write their names formed the words "Dainippon Teikoku," the "Empire of 'Great' Japan," which was the official name of Japan until 1947.

These four firms still remain affiliated, which is why my driver knew what I was referring to. He responded with "よくご存知ですね" ("Yoku go-zonji desu ne," "You are well acquainted").