On August 15, 2015, the world observes the 70th anniversary of the end of the Second World War in the Pacific Theater. This edition of AMTI commemorates the conclusion of the conflict and its legacy for maritime Asia. Read special features on the strategic role that maritime Asia played for the victorious allies, including the United States, European powers, and the Soviet Union, as the war ended. Below, view 15 maps that help to explain why the Pacific Theater looked the way it did in August 1945, and why the conclusion of the conflict continues to shape geopolitics in East Asia today.

15 Maps that Explain the End of World War II in Maritime Asia


Pre-World War II China
Pre-World War II China

Pre-World War II China

Warlords controlled vast swathes of territory in inter-war China and Nationalist control of the country was limited. Following the Marco Polo Bridge Incident in early July 1937, the nationalist government was unable to mount a fulsome response to the ensuing Japanese invasion. By the end of August, Beijing and Tianjin had fallen to Japan.

WW2 Maritime Asis, September 1939
WW2 Maritime Asis, September 1939

September 1939

The United States, France, Britain, the Netherlands, and Portugal all held colonies in the Asia-Pacific prior to Japanese expansion into China, Formosa, and Korea.

Japanese Centrifugal Offensive, December 1941
Japanese Centrifugal Offensive, December 1941

Japanese Centrifugal Offensive, December 1941

In December 1941, Japan’s Centrifugal Offensive was launched to gain control of the Western colonies in Southeast Asia and create a defensive perimeter to protect against an Allied offensive. It succeeded in capturing most U.S., British, and Dutch held territory. By the end of February 1942, Tokyo had secured all Western colonial possessions with the exception of part of New Guinea and Macau.

Major Japanese War Objectives and Planned Opening Attacks
Major Japanese War Objectives and Planned Opening Attacks

Major Japanese War Objectives and Planned Opening Attacks

Japan expanded rapidly between 1941 and 1942, expelling virtually all colonial powers from the region. The only exceptions were in parts of New Guinea, where a handful Australian, Dutch, and native Papuan soldiers led a guerrilla war, and Portuguese Macau, which became a Japanese protectorate in 1943 after Japan installed “advisers” (in lieu of occupying them). The map also states the mission of Japanese forces in each area.

Major Operations in the Pacific Theater
Major Operations in the Pacific Theater

Major Operations in the Pacific Theater

The United States’ island hopping campaign led by General Douglas MacArthur and Admiral Chester Nimitz allowed it to advance toward Japan without getting bogged down in heavy combat at every island. The campaign focused on islands that were not heavily defended yet still had strategic value for advancing toward Japan. After capturing an island, the United States would establish a small military base and airstrip to facilitate the attack on the next target.

American Carrier Operations December 7, 1941 - April 18, 1942
American Carrier Operations December 7, 1941 – April 18, 1942

American Carrier Operations December 7, 1941 – April 18, 1942

From 1941 to 1942 the United States carried out a number of carrier operations to support amphibious assaults against Japanese forces and maintain control over Allied territory. These ultimately allowed the United States to control enough islands near Japan to conduct strategic bombing missions on the Japanese mainland.

Soviet Offensive into Machukuo
Soviet Offensive into Machukuo

Soviet Offensive into Machukuo

Following the defeat of Hitler in Europe, the Soviet Union launched a massive invasion of Manchuria in August 1945 – despite having signed a neutrality pact with Japan in 1941. At the Yalta Conference in February 1945, Stalin had agreed to attack Japan three months after defeating Germany. Between August 9 and September 2, 1945, the Soviet army was able to gain control over northern Korea, Sakhalin, the Kuril Islands, Inner Mongolia, and Manchuria.

Japanese Force Dispersion
Japanese Force Dispersion

Japanese Force Dispersion

As the Pacific war drew to a close and Japan prepared for a U.S. invasion, approximately four million Japanese troops held strategic points where the Japanese leadership anticipated the Allies would attempt an invasion.

Operation Downfall
Operation Downfall

Operation Downfall

Prior to the detonation of the atomic bombs in Hiroshima and Nagasaki, the United States planned to invade Japan in Operation Downfall. “Downfall” was divided into Operation Olympic and Operation Coronet. Operation Olympic was designed to capture the southern part of Kyūshū so that it could be used as an airbase and staging area for Operation Coronet, which was a larger-scale invasion focused on capturing Tokyo. Casualty projections ranged from about half a million people to up to four million people.

China at the End of World War II
China at the End of World War II

China at the End of World War II

In August 1945, Japan still held much of China, though the China Communist Party was gaining control of the northeast.

Summary of Allied Pacific Campaigns and Status of Japanese Forces, February 1, 1945
Summary of Allied Pacific Campaigns and Status of Japanese Forces, February 1, 1945

Summary of Allied Pacific Campaigns and Status of Japanese Forces, February 1, 1945

Toward the end of the war, Japan still controlled much of the area it had at its height in 1942. While the British had retaken most of Burma and the Soviets were advancing through Manchuria and Sakhalin, Japan still controlled most of Southeast Asia and a large part of China. In the Pacific, the Allies had regained most of the Philippines, most of New Guinea, a small part of Borneo, and a handful of islands. Due to the success of the United States’ island-hopping campaign and strategic bombing, the Allies were able to win the war without invading the vast majority of Japanese held territory.

Estimated Japanese Strength on or about August 15, 1945
Estimated Japanese Strength on or about August 15, 1945

Estimated Japanese Strength on or about August 15, 1945

As fighting concluded in the Pacific Theater, an estimated 4.9 million Japanese soldiers remained stationed throughout the Pacific Islands and Asia.

As fighting concluded in the Pacific Theater, an estimated 4.9 million Japanese soldiers remained stationed throughout the Pacific Islands and Asia.

At the conclusion of the war, Japan was still extended throughout the Pacific as Allied offensives continued to chip away at its holdings.

Areas Under Allied and Japanese Control, August 15, 1945
Areas Under Allied and Japanese Control, August 15, 1945

Areas Under Allied and Japanese Control, August 15, 1945

At the conclusion of the war, Japan was still extended throughout the Pacific as Allied offensives continued to chip away at its holdings.

Japanese Colonial Holdings on September 2, 1945
Japanese Colonial Holdings on September 2, 1945

Japanese Colonial Holdings on September 2, 1945

Officially Japan surrendered on September 2, 1945, although some units surrendered as late as September 12th. The accompanying map depicts Japan’s unit-specific dates of surrender.

Territorial Clauses of the Japanese Peace Treaty
Territorial Clauses of the Japanese Peace Treaty

Territorial Clauses of the Japanese Peace Treaty

Attached to the San Francisco Peace Treaty of 1951, this map illustrates the territory Japan relinquished in the postwar settlement. Chapter II, Articles 2 and 3 of the Treaty are included in small print indicating the treaty’s territorial clauses with relevant island groups marked as shown. These include the Kuril Islands/Northern Territories, the Ryukyu Islands (including the Senkakus), and the Spratly and Paracel Islands.

What the San Francisco Treaty map does not depict is the ambiguity that surrounded the ultimate disposition of several of the territories that Japan relinquished in 1951. Under Article 2(c), the Kuril Islands were definitively transferred to the USSR, but the treaty did not clarify whether the four islands that Japan identifies as the Northern Territories were part of this chain. Under Article 2(f), Japan renounced all claims to the Spratlys and Paracels, but the treaty did not specify to which country they would be given. Under Article 3, the Ryukyu Islands, including the Senkakus, were left in the trusteeship of the United States. In 1951, Secretary of State Dulles coupled this with a verbal pronouncement that Japan retained residual sovereignty. This was only contested after two decades of U.S. administration as Washington prepared to return the island chain to Tokyo as part of Okinawa Reversion.

In these two treaty articles we find the seeds of some of the region’s most intractable territorial issues. This legacy of ambiguity in the postwar settlement is the inheritance of 21st century maritime Asia.

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