The proclamation of Taika no Kaishin (Great Reformation of the Taika Era) announced in 646 tells that 'the capital was established for the first time' and 'it placed a cho (leader) in every bo (approximately 550-meter-square city block bounded by major streets) and rei (senior leader) in every four bo, which suggests the introduction of Chinese Tojo system to Japan in fairly early times.
646年、大化の改新の改新の詔に「初めて京師を修む」とあり、「京は坊毎ニ長一人を置き、四坊に令一人を置く」となっており、古くから中国の都城制が知られていたことがうかがわれる。