From colonial divergence to regional complementarity: path dependency and inter-urban specialization in Qingdao and Dalian

Why do some historically proximate port cities develop complementary rather than competitive trajectories? This paper examines Qingdao and Dalian to show how colonial planning regimes have produced enduring patterns of inter-urban specialization. German administration in Qingdao (1898–1914) institutionalized comprehensive urban planning and manufacturing-oriented land use, while Japanese rule in Dalian (1905–1945) promoted a free-port model emphasizing logistics, warehousing, and transshipment. Drawing on comparative historical analysis and port operations data (2010–2024), the paper traces how these distinct planning logics became embedded through institutional layering, infrastructure-led increasing returns, and post-1949 policy choices that reinforced inherited spatial and functional divisions. The findings demonstrate how colonial-era planning institutions can generate durable forms of inter-urban complementarity, challenging assumptions that geographically proximate port cities necessarily converge through coordinated planning or market competition.