Water moat and dry moat are respectively thought to have its origin in the midstream of the Yangtze River and in Inner Mongolia (where the Xinglongwa Culture flourished), and were built in various places on the Japanese archipelago since the Yayoi period until the medieval period.
「環濠」と「環壕」のルーツはそれぞれ、長江中流域と内蒙古（興隆窪文化）であると考えられており、日本列島では、弥生時代と中世にかけて各地で作られた。