Mentioning the Tsushima Strait, what comes to mind is the famous naval battle of Tsushima in history, which was the decisive battle of the Russo-Japanese War, the first great power war in the 20th century. The Russo-Japanese War was even called “the zero World War” because of its scale and influence, while Japan regarded it as “a war concerning the survival of the empire”. Russia’s southward march in search of an ice-free port was interrupted, its ambition to monopolize Italy was curbed, Japan became a member of the great Powers, and the Korean Peninsula was reduced to Japan’s sphere of influence.
Tsushima Strait is located at the western edge of the North Pacific Ocean and the southwestern end of the Sea of Japan. It is an important strategic maritime route and a place of great strategic importance for military commanders. As a separate channel, tsushima Strait and Jeju Strait, Busan Strait, Ikki Strait, jimima Strait constitute the broad Sense of the Korean Strait. Japan is different from other countries in naming the Tsushima Strait. Japan refers to the choson Strait as tsushima Strait, busan Strait as Tsushima Strait West channel, and Tsushima Strait As Tsushima Strait East Channel. The term “Tsushima Strait” as used in this article refers to what China traditionally calls the waters between the Japanese tsushima and Iki islands. Tsushima Strait has a very high strategic position and geopolitical value. In history, the Naval battle between Japan and Russia made the Tsushima Strait War famous. In recent years, it has attracted great attention from countries inside and outside the region. At present, as the strategic value of the Tsushima Strait continues to increase and countries inside and outside the region have deepened their understanding of it, the struggle and cooperation around the Tsushima Strait has also been strengthened. Tsushima Strait is of great significance for China to break through the siege at sea and enter the deep ocean. In this regard, China should constantly improve its maritime power, strengthen its strategic presence in the Tsushima Strait, build itself into a maritime power, and respond to a series of strategic games in the Tsushima Strait with a more positive attitude.
The strategic position and value of tsushima Strait
Tsushima Strait occupies a unique geographical position. Tsushima island divides the middle channel of the Korean Strait into two parts: the sea area between Tsushima Island and Busan is the Busan Strait; The sea area between Tsushima island and Iki Island is tsushima Strait. Tsushima Strait can be seen in all directions: from tsushima Strait to the southwest to the East China Sea, through the Korean Strait to the west can be connected with the Yellow Sea of China, east through the Kanban Strait, Seto inland Sea can reach the Pacific Ocean, north through the Sea of Japan out of the Tatar Strait to the Sea of Okhotsk.  Tsushima Strait and Busan Strait, as the only and “throat” way in and out of the Sea of Japan, have become the “south gate” guarding the Sea of Japan, and their strategic position is very prominent.
During the Cold War, the Soviet Union, Japan and the United States all attached great importance to the geostrategic position of tsushima Strait, and the competition around tsushima Strait was extremely fierce. In the 1970s, the Soviet Navy rose rapidly, with its Pacific fleet regularly sailing through Japan and the nearby Tsushima, Soya and Tsukaru straits throughout the Pacific, South China Sea and Indian Ocean.  In order to cope with the imminent threat of the Soviet Union, Japan took the Japan-US alliance as the cornerstone, tried to contain the Soviet Union by relying on the strength of the United States, continuously improved anti-submarine and air defense capabilities, and strengthened monitoring of strategic maritime routes such as tsushima Strait. The “forward strategy” set out in the Us Maritime Strategy, a 1986 maritime guidance document, required the US Navy to control 16 of the world’s most important “strategic waterways”, one of which was the Tsushima Strait. These channels can control not only the sea lines of communication, but also almost all the trade and military routes in the world, thus helping the United States to dominate the world. After the end of the Cold War, the US Navy implemented the strategy of “sea-to-land”, dividing the global strait for international navigation into eight regional strait groups connecting and supporting each other from north to south , among which the Northeast Asia Strait Group includes tsushima Strait.
Tsushima Strait has important economic value, especially its shipping value and fishery value. As the continental shelf under tsushima Strait extends completely and the terrain at the bottom of the strait is relatively gentle, the average water depth of tsushima Strait reaches 50 to 100 meters, and the entrance and exit are relatively spacious, which is conducive to the navigation of ships. The Route between the Far East and the west coast of North America, one of the main routes in the Pacific Ocean, has to pass through the Tsushima Strait and cross the Sea of Japan before entering the Pacific Ocean. This route runs through the Pacific Ocean and is a “busy route” worthy of the name. It connects the Far East with the most dynamic economy in the world and North America with the strongest economic strength. The two regions have a large population, a large trade volume and an amazing economic aggregate. In addition, the natural ports of Shimonoseki, Kitakyushu, Nagasaki, Fukuoka and Kanban along the coasts of Honshu and Kyushu in Japan have also vigorously promoted the shipping development along the Tsushima Strait and promoted the prosperity of maritime trade in Northeast Asia. The existence of tsushima Current makes the strait warm and humid, with abundant plankton and Marine plants. At the turn of winter and spring, the convergence of the ice water from the Sea of Japan and the warm current will flood the nutrients deposited on the seabed, thus enriching the fishery resources in tsushima Strait.
It is of great political value to the Strait. Although the Tsushima Strait lies between The Japanese islands of Tsushima and Iki, the territorial sea law enacted by Japan in 1977 and the Territorial Sea and Contiguous Zone Law enacted in 1996 defined the territorial sea in the Tsushima Strait as 3 nautical miles instead of the internationally recognized 12 nautical miles. In accordance with the United Nations Convention on the Law of the Sea (UNCLOS), the Tsushima Strait is an international waterway where all countries enjoy the freedom of navigation and overflight. It is mainly used for international navigation. Therefore, the Tsushima Strait is of great political value to all countries and is a key international strategic passage.
The Tsushima Strait is of great military value and has been contested by military forces since ancient times. In modern times, tsushima Strait gradually became a springboard for Japan to invade the Korean Peninsula and challenge Tsushima Russia. After the Meiji Restoration, With its rapidly growing national strength, Japan brought Korea into its sphere of influence by occupying by force, and continuously shipped the rich resources of Korea back to Japan through the Tsushima Strait. The Russo-Japanese War of 1905 ended with Japan’s complete victory in the naval battle against Malaysia. This overwhelming victory provided Japan with a new sense of superiority, so that Japan entered the era of militarism; Russia lost the ability to conduct naval operations in the Far East, leaving only a handful of ships in the Baltic.  Tsushima Strait also witnessed the rise of Japan as a world power and the fundamental changes in the pattern of Northeast Asia.
Attitude and behavior of countries in and outside the Region towards tsushima Strait
Geographically, the tsushima Strait is directly related to Japan, South Korea, China and Russia, and the four countries in the region are surrounded by the Tsushima Strait. For a long time, the United States, as a major country outside the region, has attached great importance to the strategic position of the Tsushima Strait. It can be said that the game between the five countries inside and outside the region has become a key factor leading the situation in the Tsushima Strait.
For Japan, the Tsushima Strait connects the Sea of Japan, yellow and East China seas and is the closest waterway to mainland East Asia. The Tsushima Strait is also close to the Dohera Strait between Kyushu and Honshu, which leads to the Seto Inland Sea, Japan’s “backyard of the sea.” Historically, Chinese civilization, Buddhist culture, advanced farming and manual techniques from China were continuously introduced to Japan through the Tsushima Strait. During the tokugawa shogunate’s reign before the Meiji Restoration, Tsushima island was the only Japanese port allowed by the shogunate to conduct trade with the Korean Peninsula, and tsushima Strait was responsible for maintaining external contacts and exchanges. Tsushima island has the title of “the front line of Japan’s national defense”, is an important strategic point of Japan. If foreign troops pass through the Tsushima Strait, they will reach Japan’s strategic hinterland on the east side of the Sea of Japan, exposing the weakness of Japan’s homeland defense. The Tsushima Strait is Japan’s “lifeline at sea”. Japan has a large military garrison around the Tsushima Strait, mainly in Sasebo, Tsushima Island, Kitakyushu and other military bases, with the purpose of monitoring and administering vessels of various countries passing through the Tsushima Strait and safeguarding Japan’s maritime rights and interests. Japan has long regarded the Sea of Japan as its own sea and the Tsushima Strait is the key to controlling the Sea. Japan has beefed up its defenses against Chinese attempts to cross the Tsushima Strait.
For the ROK, as it is geographically close to the Tsushima Strait, any movement of the strait will attract the ROK’s high attention. Japan’s invasion of Korea through the Tsushima Strait in history is a painful memory that South Korea is still unable to erase. The Tsushima Strait also has an overall significance for South Korea’s national survival and security. On the Busan Strait side, South Korea has deployed two naval bases in Jinhae and Busan. Among them, the Jinhae Naval Base is the most important naval base in South Korea and the largest and strongest in terms of base size, ship class and number. As the largest port and the second largest city of South Korea, the importance of the naval base in Busan has decreased due to the completion and operation of the Jinhae Naval base. However, advanced warships such as chungmugong Yi Sun-shin class guided-missile destroyers are still stationed in Busan, and powerful troops such as the Fifth Battle Regiment of the South Korean Navy are stationed there. It is not hard to see that South Korea and Japan are both Allies of the United States, but due to historical and realistic factors, South Korea is still wary of Japan.
For China, the Tsushima Strait is key to breaking through the FIRST ISLAND chain of the United States into the Sea of Japan and the Northwest Pacific. In recent years, Chinese navy warships and air force jets have repeatedly crossed the Tsushima Strait into the Sea of Japan for routine training. In January and August 2016, the Chinese Air Force’s light transport aircraft Y-9 and AEW (Y-8) passed through tsushima Strait airspace for the first time. In August 2016, H-6K bombers of the Chinese Air Force flew over the Tsushima Strait for the first time on their way to scarborough Shoal in the South China Sea.  This caused great concern in Japan and the United States, and Japan even sent ships and planes to track and monitor and release “follow photos” every time. As a matter of fact, the Sea of Japan does not belong exclusively to Japan, still less does it fall within the sphere of influence of the United States. China’s passage through the Tsushima Strait is completely lawful, reasonable and justified.  When crossing the Tsushima Strait became normal, China broke through the blockade of the First island chain of the United States and began to go to the deep sea, with its ocean-going capacity greatly improved. At a time when the U.S. and Japan are increasingly harassing The South China Sea and East China Sea, the Chinese navy and air force entered the Sea of Japan through the Tsushima Strait.
For Russia, tsushima Strait is one of the core routes for its Pacific fleet from the far East port to the Pacific Ocean, and crossing tsushima Strait has become an inevitable choice for the Russian navy and air force. Russia was humiliated in the naval war against Malaysia, and the unresolved historical grievances and mistrust between Japan and Russia became the historical driving force for Russia to set foot in the Tsushima Strait. As early as 1999, the Russian Ministry of National Defense issued the Naval Strategy of the Russian Federation, which determined that the Russian naval military strategy at the beginning of the 21st century must emphasize the status and role of key strategic passages at sea. Russia believes that the major maritime powers in the world today generally deploy part of their strategic nuclear forces at sea, and the modern navy can monitor and control the maritime situation, threaten other countries’ maritime passages with its own strong naval strength, and thus control the stability and development of the world. Russia’s economic and trade development needs a safe maritime situation and smooth maritime traffic network, so Russia takes as its naval strategic task to ensure the traffic line closely related to its own interests within its ability. As for the Tsushima Strait, which is mainly radiated by the US, Japan and South Korea, Russia is unable to exert a decisive influence due to its limited naval military expenditure, but this cannot stop Russia from ensuring the safety of the maritime traffic line and moving forward. In recent years Russia has repeatedly sent warships and aircraft through the Tsushima Strait to show its resolve and presence.
For the United States, the Tsushima Strait is a “lock” blocking major countries in the western Pacific, and strengthening the military presence in the Strait is a key link in the implementation of northeast Asia strategy. First of all, the United States around the tsushima strait deployment of base in yokosuka, Japan as the core, external radiation and Okinawa, sasebo, thick wood and white beach South Korea busan, zhenhai base echo each other to form a mesh, able to cope with challenges from China, Korea, Russia, the United States and its Allies in interests, the influence of the United States in northeast Asia. Secondly, the military presence in the Tsushima Strait area also enables the United States to act as a mediator between Japan and South Korea, effectively coordinating existing or potential conflicts and balancing the two countries’ relations. Third, although Japan and the ROK are Allies of the United States, the forward military deployment of the United States in the Tsushima Strait and even the entire Northeast Asia region can restrain the pursuit and ambition of developing military forces of Japan and the ROK.
With the continuous rise of China, the Obama administration and the Trump administration both regard China as a major strategic competitor and put more emphasis on the deployment of military forces in the Asia-Pacific region. They try to draw in Japan and South Korea to limit and encircle China, while marginalizing Russia.
China’s strategic response
China has gradually established the maritime power strategy of “persisting in coordinating land and sea development and accelerating the building of a maritime power” to guide the steady development of various maritime undertakings in China.  The special geographical location and strategic position of tsushima Strait is of great significance to China. It is closely related to China’s own interests, maritime security and foreign trade development. In dealing with the complex game between countries in the Tsushima Strait, China should thoroughly implement Xi Jinping’s strategic thought of becoming a maritime power, give full play to its own advantages and subjective initiative, and ensure that China’s maritime rights and interests are not infringed upon by other countries.
First of all, China’s navy is undergoing rapid modernization, its maritime power is increasingly enhanced, its far-ocean strength is constantly enhanced, and China is speeding up its efforts to become a maritime power. By 2020, the two aircraft carrier battle groups of the PLA Navy have become combat-ready, and the construction of various advanced ships and aircraft is accelerating. The blue-water Navy has begun to take shape. The growth of hard power and the strength of the sea gives China more confidence and more options in the competition for the Strait in the future. If the Tsushima Strait is opened, the first island chain of the United States can be broken.
Secondly, the current strategic competition between China and the United States is a comprehensive and multi-field competition between major countries, and the competition for maritime traffic arteries is an important part of it. The United States has long been in the first island chain, especially the tsushima strait built a large number of military bases, a key waters and deployed a large number of military personnel and weapons and equipment, now is more frequent, increasing, strengthen the personnel quantity and quality, through information sharing, technology export woo, Japan and South Korea two Allies to strategic encirclement of China, It hopes to use its comparative advantage to block China in the offshore waters and maintain its maritime hegemony. Japan and South Korea have vague attitudes towards sino-US strategic competition and the US containment of China. On the one hand, Japan and the ROK are increasingly worried and suspicious of their neighbor China, which is becoming stronger and more important than ever before. It has become a priority for both countries to get a free ride on the US and use its strength to contain China. On the other hand, Japan and South Korea have to work hard to maintain good relations with China because of the huge and close trade between China and the two countries, and the two countries are very ambivalent about China. In this regard, China not only needs to work hard to maintain its relations with the US in its dealings with the US, but also needs to stick to the bottom-line thinking, unswervingly take countermeasures on the bottom-line issues. At the same time, we need to develop our relations with Japan and the ROK, find more common interests, create a sound atmosphere for cooperation and defuse mistrust and insecurity. Moreover, China also needs to maintain a continuous crossing of the Tsushima Strait and show its influence through its air and sea presence.
Third, with the global warming, the Arctic Sea ice is rapidly disappearing, and it is expected that in the near future, the Arctic Ocean will become navigable in summer or year-round.  from northern Europe through the arctic — bering strait “northeast” route to the far east and from the east coast of North America through the arctic — bering strait “northwest airlines” more and more by the attention, once the two routes open throughout the year, the east sea route to the far east from Europe and the americas will significantly shorten the 1/3 to 2/3, and the two routes to China, southeast Asia, The best option is to go through the Tsushima Strait.  It can be seen that the shipping value of tsushima Strait will continue to rise in the future, and the competition between countries inside and outside the region will also become increasingly fierce.
Therefore, China needs to strengthen dialogue and communication with countries inside and outside the Tsushima Strait region in terms of international laws, international institutions, crisis management and dispute management, and establish and improve the economic and security guarantee system related to the Tsushima Strait. At the international legal level, China should give full play to the effectiveness of the United Nations Convention on the Law of the Sea (UNCLOS) and carefully study the provisions of the UnCLOS on major maritime public transport routes, so as to provide legal support for China’s peaceful use of the Tsushima Strait. In terms of international institutions, China should work with four countries inside and outside the region, Japan, South Korea, the United States and Russia, to formulate institutional norms concerning the Tsushima Strait as soon as possible, especially the security mechanism and shipping system, which will be conducive to the economic activities of all countries on a unified and orderly basis. In terms of crisis management and risk management, China should establish unimpeded communication channels with other countries in the region, strengthen regular exchanges and consultations with other countries on issues, and have complete response plans and measures for emergencies to minimize the probability of crisis and risk.