Why are China's four provinces of mountains and rivers considered the core stronghold, while coastal areas are more prone to revolutionary forces?

From a long-term structural perspective, this difference primarily stems from the distinct modes of economic and population organization.
The four provinces of mountains and rivers (Hebei, Shandong, Henan, Shanxi, etc.) have long been based on intensive agriculture, with a high proportion of small-scale farming, relatively stable populations, and social relationships more often built on familiar networks and land ties.
Their dietary structure is mainly high in carbohydrates, salt, and storage-resistant foods, which is essentially an adaptation to stable production and low-volatility environments.
In this structure, individual income and livelihood security depend more on land, family, and institutional arrangements, leading to a higher reliance on existing order, and society tends to operate more towards maintaining the continuity of the established framework.
In such a structure, their role in dynastic cycles or social upheavals is more about supporting population capacity, grain production, and maintaining grassroots order, thus often summarized as the "fundamental base."
In contrast, coastal areas, due to port economies, foreign trade, and population mobility developing earlier, have a more market-oriented and outward-looking economic structure.
Income sources rely more on trading opportunities, cross-regional connections, and individual capabilities rather than fixed resource distribution.
In this highly mobile structure, sensitivity to rule adjustments, resource reorganization, and institutional changes is higher, and adaptation tends to involve seeking new balances through change itself.
Therefore, during periods of historical transformation or institutional shifts, these regions are more likely to see populations involved in constructing new systems, transitioning economic models, or updating ideas, and are often described as areas where "revolutionary forces are more active."