In contrast to Jomon and Yayoi types that were strongly regional in characteristic, Haji is found distributed widely from Honshu to Kyushu islands, based on identical design and production method, although some regional traits can also be found if scrutinized closely.
縄文式土器、弥生式土器は地域色が強かったのに対し、土師器では、厳密に言えば地方色もあるが、同じような意匠・技法による土器が本州から九州までの規模で分布する。