What are the "sea power" and "land power" theories in geopolitical theory?

(1) Location: The ideal location is a centrally located island, close to major trade routes, with good harbors and naval bases. For example, Britain was separated from Europe by the English Channel, which was not only a barrier of water, but also close to the continent. Therefore, Britain did not need to maintain a continental army, but could concentrate on the development of sea power, and blockade the ports of the continent and control the routes in and out of the northern part of Europe with its superior navy. In sharp contrast to Britain, France not only had to maintain a continental army, but also had to divide its navy between the Atlantic Ocean and the Mediterranean Sea. Therefore, in the competition for sea power, France was naturally at a disadvantage to Britain.

(2) Topography: The coastline of a country is part of its boundaries. Where a country's boundaries are easily accessible to the outside world, it is easier for its people to develop and interact with the outside world. Flat terrain and fertile land may make a people reluctant to move to the sea, as in the case of France; on the other hand, it may force the people to live by the sea, as in the case of Holland and Portugal. The island and peninsular countries, limited by their topography, must emphasize the development of sea power if they want to become strong.

(3) The size of the country: Ma believed that the size of the country must be matched with its population, resources and other factors of power. The ratio of the total population of a country to the total length of its coastline was of great importance. Otherwise, a large territory may become a weakness. If a country is too large and its population is disproportionate to its resources, it will have a low density of defense, which makes the country more dangerous, and if it is cut off by rivers or ports, it will be a major weakness. In the case of the American Civil War, for example, the South was too large in terms of population and resources, especially with a long coastline and too many inland waterways, which made it easy for troops to be divided and lead to defeat.

(4) Population: The quantity and quality of the population is an important basis for the right to the sea, the right to the sea countries should not only have a considerable number of people engaged in navigation, and the number of people who participate in the sea life directly should stand a high proportion. The usual seafaring business of a country (including shipping and trade) is enough to determine the staying power of its navy in war. This is exemplified by the United Kingdom, which is not only a seafaring nation, but also a shipbuilding and trading nation, with the necessary human and technological resources for the development of sea power.

(5) Nationality: The psychological factor of national willingness to trade on the sea and the ability to produce seafaring is also very important. Everyone is proud of seeking wealth from the sea, so the maritime business naturally flourishes. The combination of maritime commerce and the navy, together with the development of colonies, eventually made Britain the hegemony of the sea.

(6) Government policy: The government had to be wise and firm in order to develop sea power in the long run. This was the main reason for Britain's success. From the time of James I, British national policy has been directed toward the pursuit of overseas colonies, maritime trade, and naval superiority.

The theory of land power

H.J. Mackinder, on the other hand, put forward the theory of the heart of the continent, arguing that the heart of the Eurasian continent became the most strategically important area with the development of land transportation. His theory became known as the land power theory and had a great impact on world politics. By the 1940s, N.J. Spykman emphasized the importance of the periphery and proposed the land-edge theory, another school of geopolitical theory in the land-rights theory. in the 1950s, A. de Seversky, based on the important role of the air force in the strategy and the overlapping areas of control of the U.S. and the Soviet air forces, put forward the theory that the Arctic region was very important to the U.S. in the struggle for air power, which was known as the air-rights theory. in 1973, S.B. Cohen proposed a geopolitical strategy model, dividing the world into two geostrategic zones: the maritime trade zone and the Eurasian continental zone. Geopolitics has become an important basis for countries to formulate policies such as defense and foreign affairs. Although the study of various geopolitical theories is based on geography, they are based on different emphases. In the past, more from the historical, political, military and other considerations, and in recent years on the role of economic, social and other aspects of the increasing importance.