How Big Was the Empire of Japan at Its Peak?

In 1943 the Empire of Japan, counting every territory it occupied, covered about 8.9 million km², measured from its outline in TrueSize. That is 10% more than the 48 contiguous US states and about 24 times modern Japan (about 378,000 km²). The figure usually quoted for 1942 is 7.4 million km²; the TrueSize outline is larger because it draws each occupied country in full. In 1938, before the Pacific War, Japan with Korea, Taiwan and its dependent state Manchukuo covered about 1.8 million km².

The Empire of Japan in 1943 and the 48 contiguous US states (about 8.1 million km²) side by side on the equator, each at its true size.

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The numbers

Region	Area	Source
Empire of Japan, 1943 (largest extent)	8.90 million km²	measured in TrueSize
Empire of Japan, 1942	about 7.4 million km²	published estimate
Empire of Japan and Manchukuo, 1938 to 1944	1.79 million km²	measured in TrueSize
Empire of Japan, 1938	about 1.98 million km²	published estimate
Empire of Japan, 1930 to 1937	0.70 million km²	measured in TrueSize
Japan today	about 0.38 million km²	official total
Contiguous 48 US states	about 8.1 million km²	official total

The 1943 outline shows how far Japanese forces reached, not a territory Japan administered in full. The 1938 to 1944 outline is the better figure for the lands Japan and its dependent state Manchukuo actually ruled. After 1941 the conquests extended Japanese control from Korea, Taiwan and Manchukuo across occupied eastern China and Southeast Asia to New Guinea. In 1943 Japan declared Burma and the Philippines nominally independent.

Year by year in the timeline

The Empire of Japan is covered by several entries in the TrueSize timeline, starting with the Meiji restoration in 1868.

Year	Area in TrueSize	What changed on the map
1868	0.27 million km²	the Meiji restoration
1875	0.38 million km²	the Kuril Islands come to Japan under the Treaty of Saint Petersburg
1895	0.40 million km²	Taiwan is ceded after the First Sino-Japanese War
1905	0.46 million km²	southern Sakhalin is added after the Russo-Japanese War
1910	0.68 million km²	Korea is annexed
1938	1.79 million km²	Manchukuo, a dependent state in Manchuria, is drawn with Japan
1943	8.90 million km²	the largest extent, after the conquests of 1941 and 1942

Japan surrendered on 2 September 1945, and its territory shrank to the home islands.

Why it looks bigger on most maps

The occupied lands reached from Manchuria and the Kuril Islands at about 50°N to New Guinea south of the equator. A Mercator map stretches the northern parts by two times or more and the southern parts hardly at all, so the empire's northern half looks larger than it was. Beside the 48 contiguous states on the equator, as above, the 1943 empire is only 10% bigger.

The Empire of Japan in 1943 at its home position, with a plain fill instead of the flag.

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The Empire of Japan and Manchukuo in 1938, before the conquests of the Pacific War.

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Try it yourself

1. Open the Home tab and click the Modern/Historical switch to open the timeline. Use Go to year and enter 1943.
2. Search for the Empire of Japan. Use the arrow keys to step through earlier and later changes in its borders, or press Play.
3. Pin it, click Today, then add Contiguous 48 or Japan from the search box and drag them side by side.

The timeline works on the web version and in the mobile app. The Stats button on the Tools tab shows the total area of what you have loaded.

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More comparisons

• The largest empires in history, compared
• How big was the British Empire?
• The Mongol Empire at true size
• How much bigger was the Soviet Union than the USA?
• Historical Borders Map: See Any Country's Borders by Year

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