China PRC military strategists view the first island chain as part of a
cordon sanitaire by the U.S. and its allies to
encircle the country and limit its
strategic depth and
maritime security. Within the first island chain, the PRC's access to the South China Sea is viewed as crucial for its navy, as the
Yellow Sea and
East China Sea are considered too shallow for clandestine submarine operations. Control over Taiwan and its deeper eastern waters would provide the
People's Liberation Army Navy's
ballistic missile submarines with less
detectable access to the wider Pacific where they would serve as an important component of a credible
second strike capability for the PRC. According to a 2018
United States Department of Defense report to
Congress, the
People's Liberation Army's
Anti-Access/Area Denial military capabilities aimed at the first island chain are its most robust. The report also stated that the People's Liberation Army Navy's ability to perform missions beyond the first island chain is "modest but growing as it gains experience operating in distant waters and acquires larger and more advanced platforms." The
Cabinet of Japan has also passed
defense white papers emphasizing the threat posed by the People's Liberation Army Navy in the first island chain. In the later years of the 2010s, Japan started deploying military assets to
Yonaguni and its other islands to counter China's presence along that area of the first island chain. Japan's strategic position in the first island chain began with US-Japan joint efforts to counter Soviet expansion. The
Japan Self-Defense Forces currently plays the role of protecting US military bases and preserving military strength in East Asia. As for Japan's Territorial Protection Self-Defense Forces, which mainly rely on islands in southern Japan adjacent to the Yellow Sea and the East China Sea, Japan has military advantages in anti-submarine, air defense and sea mine technologies. In 2026, Japan and the U.S. agreed to expand joint military training across the first island chain.
Philippines In 2021,
Lloyd Austin, on behalf of the United States, thanked his counterpart in the Philippines
Delfin Lorenzana for retaining the 70-year-old
visiting forces agreement between the two nations. In 2023 four new bases were announced in the Philippines.
South Korea South Korea has been described as an anchor along the first island chain. In 2025, a
United States Forces Korea commander stated that U.S. forces on the Korean peninsula will expand their scope of operations to prepare for a potential
defense of Taiwan. It is located at the midpoint of the first chain and occupies a strategic position.
Submarine detection and tracking is less difficult on Taiwan's western coast where the waters are shallower than on Taiwan's eastern coast.
United States U.S. General
Douglas MacArthur pointed out that before
World War II, the US protected its western shores with a line of defense from
Hawaii,
Guam, to the
Philippines. However, this line of defense was attacked by Japan with the
Pearl Harbor bombing of 1941, thereby drawing the U.S. into the war. The US subsequently launched the air
Raid on Taipei (called Taihoku under Japan's empire) and launched the
atomic bombings of Hiroshima and Nagasaki. The WW2 victory allowed the US to expand its line of defense further west to the coast of Asia, and thus the US controlled the first island chain. Between the end of WW2 and the
Korean War, MacArthur praised Taiwan, located at the midpoint of the first island chain, as an '
unsinkable aircraft carrier'. In April 2014, the
United States Naval Institute (USNI) assessed that the first island chain is the most effective point to counter any Chinese invasion. A June 2019 article published by the United States Naval Institute (USNI) called for the navy to establish and maintain a blockade around the first island chain if the US was go to war with China.
Andrew Krepinevich argued that an "archipelagic defense" of the countries that make up the first island chain would make up a big part of the implementation of the
national defense strategy of 2018. A 2019 report by the
Center for Strategic and Budgetary Assessments "proposes a U.S. military strategy of Maritime Pressure and a supporting joint operational concept, “Inside-Out” Defense, to stabilize the military balance in the Western Pacific and deny China the prospect of a successful fait accompli." The first island chain plays a central role in the report. In 2020, the
United States Marine Corps started shifting its tactics in conjunction with the
United States Navy to be deployed along or near the first island chain. ==See also==