maintenance

public order

the inside of prefecture of Japan which is suffixed "都" (To) / the inside of Tokyo-To / the inside of other administrative area which is suffixed "都" (To) when translated into Japanese (e.g. Bangkok)

metropolitan police

the Tokyo Metropolitan Police Department, the police department serving Tokyo Metropolis

maintain, keep

Tokyo (a prefecture, the capital city of Japan, consisting of 23 special wards) / Short for 東京都 (Tōkyō-to) the capital prefecture of Japan

(historical) an eastern capital

(historical) the capital of 東漢 (Tōkan, “Eastern Han”) or 後漢 (Gokan, “Later Han”), corresponds to modern Luoyang / (historical) the capital of 北宋 (Hokusō, “Northern Song”), corresponds to modern Kaifeng

(historical) Tonkin (northern region of Vietnam)