青あお線せん区く域いきあおせんくいきじ字FuriganaMeanings1nounblue-line area; illegal prostitution zonehistorical termHistorical term for areas marked with a blue line on police maps where illegal prostitution occurred, roughly from the 1940s until the 1956 Anti-Prostitution Law. Often contrasted with 赤線区域 (red-line district).See also: 青線地帯戦せん後ごの東とう京きょうには、青
