In 1800, the population of Japan was just over 30 million, a figure which would grow by just two million in the first half of the 19th century. However, with the fall of the Tokugawa shogunate and the restoration of the emperor in the Meiji Restoration of 1868, Japan would begin transforming from an isolated feudal island, to a modernized empire built on Western models. The Meiji period would see a rapid rise in the population of Japan, as industrialization and advancements in healthcare lead to a significant reduction in child mortality rates, while the creation overseas colonies would lead to a strong economic boom. However, this growth would slow beginning in 1937, as Japan entered a prolonged war with the Republic of China, which later grew into a major theater of the Second World War. The war was eventually brought to Japan's home front, with the escalation of Allied air raids on Japanese urban centers from 1944 onwards (Tokyo was the most-bombed city of the Second World War). By the war's end in 1945 and the subsequent occupation of the island by the Allied military, Japan had suffered over two and a half million military fatalities, and over one million civilian deaths.

The population figures of Japan were quick to recover, as the post-war “economic miracle” would see an unprecedented expansion of the Japanese economy, and would lead to the country becoming one of the first fully industrialized nations in East Asia. As living standards rose, the population of Japan would increase from 77 million in 1945, to over 127 million by the end of the century. However, growth would begin to slow in the late 1980s, as birth rates and migration rates fell, and Japan eventually grew to have one of the oldest populations in the world. The population would peak in 2008 at just over 128 million, but has consistently fallen each year since then, as the fertility rate of the country remains below replacement level (despite government initiatives to counter this) and the country's immigrant population remains relatively stable. The population of Japan is expected to continue its decline in the coming years, and in 2020, it is estimated that approximately 126 million people inhabit the island country.

PERIOD: 1920, 1925, 1930, 1935 (every Oct. 1). NOTE: (The de facto population is based on where individuals were living as residents when the survey was conducted.) (Every 5 years as of October 1). SOURCE: [Survey by the Statistics Bureau, Imperial Cabinet; Statistics by government offices, overseas territories of Japan].

In 1938, the year before the outbreak of the Second world War, the countries with the largest populations were China, the Soviet Union, and the United States, although the United Kingdom had the largest overall population when it's colonies, dominions, and metropole are combined. Alongside France, these were the five Allied "Great Powers" that emerged victorious from the Second World War. The Axis Powers in the war were led by Germany and Japan in their respective theaters, and their smaller populations were decisive factors in their defeat. Manpower as a resource In the context of the Second World War, a country or territory's population played a vital role in its ability to wage war on such a large scale. Not only were armies able to call upon their people to fight in the war and replenish their forces, but war economies were also dependent on their workforce being able to meet the agricultural, manufacturing, and logistical demands of the war. For the Axis powers, invasions and the annexation of territories were often motivated by the fact that it granted access to valuable resources that would further their own war effort - millions of people living in occupied territories were then forced to gather these resources, or forcibly transported to work in manufacturing in other Axis territories. Similarly, colonial powers were able to use resources taken from their territories to supply their armies, however this often had devastating consequences for the regions from which food was redirected, contributing to numerous food shortages and famines across Africa, Asia, and Europe. Men from annexed or colonized territories were also used in the armies of the war's Great Powers, and in the Axis armies especially. This meant that soldiers often fought alongside their former-enemies. Aftermath The Second World War was the costliest in human history, resulting in the deaths of between 70 and 85 million people. Due to the turmoil and destruction of the war, accurate records for death tolls generally do not exist, therefore pre-war populations (in combination with other statistics), are used to estimate death tolls. The Soviet Union is believed to have lost the largest amount of people during the war, suffering approximately 24 million fatalities by 1945, followed by China at around 20 million people. The Soviet death toll is equal to approximately 14 percent of its pre-war population - the countries with the highest relative death tolls in the war are found in Eastern Europe, due to the intensity of the conflict and the systematic genocide committed in the region during the war.

Historical chart and dataset showing total population for Japan by year from 1950 to 2025.

Those residing in Japan as of 0:00h, civilians in military employ residing abroad, etc.

Chart and table of population level and growth rate for the Nagasaki, Japan metro area from 1950 to 2025.

It is estimated that the Second World War was responsible for the deaths of approximately 3.76 percent of the world's population between 1939 and 1945. In 2022, where the world's population reached eight billion, this would be equal to the death of around 300 million people.

The region that experienced the largest loss of life relative to its population was the South Seas Mandate - these were former-German territories given to the Empire of Japan through the Treaty of Versailles following WWI, and they make up much of the present-day countries of the Marshall Islands, Micronesia, the Northern Mariana Islands (U.S. territory), and Palau. Due to the location and strategic importance of these islands, they were used by the Japanese as launching pads for their attacks on Pearl Harbor and in the South Pacific, while they were also taken as part of the Allies' island-hopping strategy in their counteroffensive against Japan. This came at a heavy cost for the local populations, a large share of whom were Japanese settlers who had moved there in the 1920s and 1930s. Exact figures for both pre-war populations and wartime losses fluctuate by source, however civilian losses in these islands were extremely high as the Japanese defenses resorted to more extreme measures in the war's final phase.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. From 1800 until 1865, Japan's fertility rate grew quite gradually, from 4.1 children per woman, to 4.8. From this point the fertility rate drops to 3.6 over the next ten years, as Japan became more industrialized. Towards the end of the nineteenth century, Japan's fertility rate grew again, and reached it's highest recorded point in the early 1920s, where it was 5.4 children per woman. Since this point it has been gradually decreasing until now, although it did experience slight increases after the Second World War, and in the early 1970s. In recent decades Japan's population has aged extensively, and today, Japan has the second oldest population and second highest life expectancy in the world (after Monaco). In contrast to this, Japan has a very low birth rate, and it's fertility rate is expected to fall below 1.4 children per woman in 2020.

PERIOD: Oct. 1, 1930, Oct. 1, 1935. SOURCE: Population Census of Japan; [Survey by the Statistics Bureau, Imperial Cabinet].

In 1800, it is estimated that approximately 9.4 million people lived in the region of modern-day South Korea (and 13.8 million on the entire peninsula). The population of this region would remain fairly constant through much of the 19th century, but would begin to grow gradually starting in the mid-1800s, as the fall of the Joseon dynasty and pressure from the U.S. and Japan would end centuries of Korean isolationism. Following the opening of the country to foreign trade, the Korean peninsula would begin to modernize, and by the start of the 20th century, it would have a population of just over ten million. The Korean peninsula was then annexed by Japan in 1910, whose regime implemented industrialization and modernization policies that saw the population of South Korea rising from just under ten million in 1900, to over fifteen million by the start of the Second World War in 1939.

The Korean War Like most regions, the end of the Second World War coincided with a baby boom, that helped see South Korea's population grow by almost two million between 1945 and 1950. However, this boom would stop suddenly in the early 1950s, due to disruption caused by the Korean War. After WWII, the peninsula was split along the 38th parallel, with governments on both sides claiming to be the legitimate rulers of all Korea. Five years of tensions then culminated in North Korea's invasion of the South in June 1950, in the first major conflict of the Cold War. In September, the UN-backed South then repelled the Soviet- and Chinese-backed Northern army, and the frontlines would then fluctuate on either side of the 38th parallel throughout the next three years. The war came to an end in July, 1953, and had an estimated death toll of three million fatalities. The majority of fatalities were civilians on both sides, although the North suffered a disproportionate amount due to extensive bombing campaigns of the U.S. Unlike North Korea, the South's total population did not fall during the war.

Post-war South Korea Between the war's end and the late 1980s, the South's total population more than doubled. In these decades, South Korea was generally viewed as a nominal democracy under authoritarian and military leadership; it was not until 1988 when South Korea transitioned into a stable democracy, and grew its international presence. Much of South Korea's rapid socio-economic growth in the late 20th century was based on the West German model, and was greatly assisted by Japanese and U.S. investment. Today, South Korea is considered one of the world's wealthiest and most developed nations, ranking highly in terms of GDP, human development and life expectancy; it is home to some of the most valuable brands in the world, such as Samsung and Hyundai; and has a growing international cultural presence in music and cinema. In the past decades, South Korea's population growth has somewhat slowed, however it remains one of the most densely populated countries in the world, with total population of more than 51 million people.

PERIOD: Oct. 1, 1935. SOURCE: Population Census of Japan; [Survey by the Statistics Bureau, Imperial Cabinet; Statistics by government offices, overseas territories of Japan].

In Japan, the crude birth rate in 1800 was 29.6 live births per thousand people, meaning that approximately three percent of the population had been born in that year. From 1800 to 1865, Japan's crude birth rate rose gradually to around 34 births per thousand people, before dropping relatively sharply to 25 over the next ten years. This was a time of great social and economic reform in Japan, as the country became increasingly urbanized and industrialized. Japan's crude birth rate reached it's highest recorded point in the early 1920s, where the number was almost 35 births per thousand people, and since then it has been decreasing gradually. There were two times in the twentieth century where Japan's crude birth rate increased, after the Second World War, and during the period of economic prosperity in the 1960s and 70s. Since 1975, Japan's crude birth rate has gradually decreased to it's lowest recorded rate ever, and is expected to be at just 7.5 births per thousand people in 2020, making it the second lowest in the world (behind Monaco).

During the Second World War, the three Axis powers of Germany, Italy, and Finland mobilized the largest share of their male population. For the Allies, the Soviet Union mobilized the largest share of men, as well as the largest total army of any country, but it was restricted in its ability to mobilize more due to the impact this would have on its economy. Other notable statistics come from the British Empire, where a larger share of men were drafted from Dominions than from the metropole, and there is also a discrepancy between the share of the black and white populations from South Africa.

However, it should be noted that there were many external factors from the war that influenced these figures. For example, gender ratios among the adult populations of many European countries was already skewed due to previous conflicts of the 20th century (namely WWI and the Russian Revolution), whereas the share of the male population eligible to fight in many Asian and African countries was lower than more demographically developed societies, as high child mortality rates meant that the average age of the population was much lower.

PERIOD: Oct. 1, 1930. NOTE: The unemployed are classified based on their last occupation before becoming unemployed. SOURCE: Population Census of Japan; [Survey by the Statistics Bureau, Imperial Cabinet].

Total, Age 0, Age 1, Age 2, Age 3, Age 4, Age 5, Age 6, Age 7, Age 8, Age 9, Age 10, Age 11, Age 12, Age 13, Age 14, Age 15, Age 16, Age 17, Age 18, Age 19, Age 20, Age 21, Age 22, Age 23, Age 24, Age 25, Age 26, Age 27, Age 28, Age 29, Age 30, Age 31, Age 32, Age 33, Age 34, Age 35, Age 36, Age 37, Age 38, Age 39, Age 40, Age 41, Age 42, Age 43, Age 44, Age 45, Age 46, Age 47, Age 48, Age 49, Age 50, Age 51, Age 52, Age 53, Age 54, Age 55, Age 56, Age 57, Age 58, Age 59, Age 60, Age 61, Age 62, Age 63, Age 64, Age 65, Age 66, Age 67, Age 68, Age 69, Age 70, Age 71, Age 72, Age 73, Age 74, Age 75, Age 76, Age 77, Age 78, Age 79, Age 80, Age 81, Age 82, Age 83, Age 84, Age 85 and over

PERIOD: At the end of every 5 years from 1898 to 1918. As of October 1st every 5 years from 1920 to 1935. NOTE: Individual towns and villages that were combined under the Municipal Government Act are counted separately. However, in the surveys in 1898 and 1903, the combined villages of Oshima County in Kagoshima Prefecture were not surveyed individually and are recorded as one combined village. The population figures in the columns for 1898 year-end to 1913 year-end are the "type A" de facto population (see page 17 of the 1916 Statistical Yearbook of Imperial Japan), while the figures for 1920, 1925, 1930, and 1935 are from the Population Censuses conducted in those years. . SOURCE: [Survey by the Statistics Bureau, Imperial Cabinet].

The Second World War was fought on such a large scale that it became total war in many countries - this is where the war effort is prioritized above all else, and the entire population and economy are mobilized to support all military endeavors. Germany and Japan were committing over 70 percent of their national income to the war effort in its final years.

There were also notable fluctuations that coincided with major events for corresponding powers. These included the UK's mobilization of its defenses in 1940, after Germany took most of Western Europe; the spike in Soviet military spending after Operation Barbarossa in June, 1941; and the U.S. entry into the war following the Pearl Harbor attacks in December, 1941.

In 1800, it is estimated that approximately 4.35 million people lived in the region of present-day North Korea. This figure would remain stagnant through much of the 19th century, increasing by just one million people over the next 110 years. The dissolution of the Joseon dynasty in the Korean peninsula in the late-1800s marked the end of centuries of Korean isolationism, and the new Korean Empire then opened itself to foreign trade and influence. By the start of the 20th century, the region of North Korea had a population of just over five million. This growth would increase dramatically following the annexation of the Korean peninsula by Japan in 1910, as extensive industrialization and modernization efforts would result in the population of North Korea doubling from just over five million at the turn of the century, to over ten and a half million by the start of the Korean War in 1950. The Korean War Following Japan's defeat in the Second World War, the Korean Peninsula was split along the 38th parallel, with a Soviet-backed totalitarian government established in the north, and a U.S.-backed authoritarian government in the south. Neither government recognized the legitimacy of the other, and an escalation of tensions saw the North invade the South in June 1950. By 1953, the North's population dropped below ten million. It is estimated that there were approximately three million total fatalities in the war, with North Korea having the largest share of fatalities of all forces involved; however, the North's isolationist and secretive policies have made it difficult to calculate the full impact of the war on the North's population. Most modern estimates suggest that more than 1.5 million North Koreans died or went missing over these three years. Following the establishment of an armistice between North and South Korea in 1953, the population of the newly-formed Democratic People's Republic of North Korea would begin to rise sharply, from 10 million at the time of armistice to almost 15 million in 1970, just twenty years later. North Korea today North Korea's population has increased in each year since the war's end, however, the rate of growth decreased in the late 1970s, as a severe economic crisis and a resulting lack of foreign technology would lead to a scaling back of many of social welfare programs for the country’s citizens. Growth would slow even further following the dissolution of the Soviet Union in 1991, as the loss of Soviet foreign aid would send the North Korean economy into a sharp decline. In the 1990s, a series of flooding, droughts, famine and economic mismanagement led to the deaths of between 500,000 to 600,000* North Koreans. Recent years have seen an improvement in political relations between both the North and South, and even sporadic improvements with the U.S., which could lead to a less-isolated North Korea in the future; however, the continued testing of nuclear weapons and allegations of widespread human rights violations have drawn widespread criticism from the international community. In 2020, it is estimated that approximately 25.8 million people reside in North Korea.

All Industries, Primary Industry, Agriculture, Forestry, Fisheries, Salt Making, Secondary Industry, Mining & Quarrying, Mining , Quarrying, Construction, Manufacturing, Ceramics, Clay & Stone mfg., Metal Industry, Machine & Tool mfg., Chemical Industry, Textile Industry, Clothing Industry, Paper & Paper Products, Leather, Bone & Feather Products, Wood & Bamboo Products, Food & Beverage, Printing & Bookbinding, Other mfg. n.e.c., Gas, Electricity & Water Supply , Tertiary Industry, Commerce, Wholesale & Retail Trade, Agency & Brokerages, Checkrooms & Lease, Finance & Insurance, Amusement & Recreation, Hotel & Restaurant Business, Other Commerce, n.e.c., Transportation & Communication, Communication, Railway & Trumway, Vessel Transportation, Other Transportation, n.e.c., Government & Military, Government, Army & Navy, Service Industry, Educational Services, Religions, Medical & Sanitary Services, Judical & Legal Services, Authorship & Art, Other Service, n.e.c., Domestic Services, Other Industries, n.e.c.

For most of the Second World War, the Soviet Union had the largest number of active military personnel each year, peaking at over 12 million people in the war's final years. The Soviet Union's ability to draw from its larger population was decisive in its eventual victory over Germany in 1945, whose eastern forces were greatly diminished by 1944 after it had already suffered heavy losses fighting the Soviets and was then forced to fight on the western front.

Each of the Great Powers had varying conscription systems in place that allowed them to draft citizens into the military. In the U.S., over 50 million men aged 18-45 would register for the draft before the war's end, and over 10 million of these were inducted into the military (alongside volunteers and those already in service). Conscription in Japan grew more aggressive as the war progressed, and its armed forces doubled in size in the final two years of the war.