The plant-derived foods from the laurel forests and fish catching in the inner bay areas were the characteristics of this cultural region; especially, approximately sixty percent of shell mounds excavated in the entire Japanese archipelago were from this cultural region.
照葉樹林帯の植物性食料と内湾性の漁労がこの文化圏の特徴で、特に貝塚については日本列島全体の貝塚のうちおよそ6割がこの文化圏のものである。