Group 1 - Shanghai household registration is one of the most sought-after in China, providing access to quality medical and educational resources, as well as more employment opportunities [1][2] - Obtaining a Shanghai household registration is notoriously difficult, often requiring high educational qualifications or employment in government institutions [3] - There exists a phenomenon where individuals from Jiangsu can easily obtain Shanghai household registration without ever residing in Shanghai, highlighting a complex "enclave" story [4][5] Group 2 - Shanghai has 11 "enclaves," accounting for one-third of the total enclaves in China, which is a unique geographical phenomenon where a piece of land is governed by an administrative district but is not connected to it [6][10] - The origins of Shanghai's enclaves date back to the early days of the People's Republic of China, when agricultural land was scarce, leading to the establishment of agricultural enclaves in Jiangsu to alleviate food shortages [8][9] Group 3 - The "Dafeng Farm," a significant agricultural enclave, has evolved into a crucial supplier of staple food products for Shanghai, with a total area of approximately 300 square kilometers [12][32] - The Dafeng Farm produces over 200,000 tons of grain annually, accounting for 20% of Shanghai's minimum grain reserve, and is a major source of pork and dairy products for the city [35][36][38] Group 4 - The relationship between Shanghai and Dafeng has transformed from a one-way supply of food to a mutually beneficial economic partnership, especially with the recent improvements in transportation connectivity [55][60] - Since the opening of the Saltong High-speed Railway in 2020, travel time between Shanghai and Dafeng has been reduced to about 2 hours, facilitating closer economic ties [53][55] Group 5 - The collaboration between Shanghai and Dafeng has led to the establishment of numerous industrial parks and projects, with over 600 Shanghai enterprises now operating in Dafeng [57][59] - The ongoing integration of the Yangtze River Delta region has positioned Dafeng as a key player in Shanghai's economic ecosystem, contributing to a new model of regional cooperation [61][63]