Next time you're in the back seat and tired of watching the meter clock up, use these ice-breakers to get the conversation flowing in your driver's language.

• Tokyo's 51,950 taxis account for 20.7 percent of the national total, with the categories broken down as follows: 31,314 hōjin (cars in company fleets); 16,787 kojin (owner-driver vehicles); and 3,849 haiyā, which operate under contract to companies or other organizations.

• "Dai Nippon Teikoku" ("Empire of Japan") refers to four major taxi firms that were merged during World War II to serve the military. The term derives from their names: Daiwa Jidosha (established in 1939), Nihon Kotsu (1929), Teito Motor Transportation (1938) and Kokusai Motorcars (1920). Even now, these four companies still enjoy a loose alliance, accepting the same voucher coupons for payment and cooperating on radio dispatches.