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.

The state of Belgium owes its name to Julius Caesar, who used the name "Belgium" to refer to the region in his narrative "The Gallic Wars". After the fall of the Western Roman Empire, the region emerged as a cosmopolitan trading center, and was a collection of smaller duchies and states (such as Flanders and Brabant), before modern history saw control of the region pass between France, the Netherlands and (to a lesser extent) Spain. Modern day Belgium emerged in 1830 following the Belgian Revolution when it gained independence from the Kingdom of the Netherlands. Throughout this time, the Belgian region was the setting of many conflicts between other European powers, which greatly affected the population development and demography of the area. From 1800 until the First world War, the population of Belgium grew steadily, and more than doubled in the nineteenth century. The World Wars Population growth stagnated in the 1910s, as a result of World War I and the Spanish Flu epidemic. Belgium was one of the focal points of military action in the war, and many military personnel from other nations also lost their lives here during the conflict. Much of the Second World War also took place in Belgium, and although it remained neutral at the outbreak of both wars, it was invaded twice by Germany due to its strategic importance. Belgium suffered an estimated 88,000 fatalities during the war; with many further military fatalities from other nations also perishing in the region. Continuous growth From 1950 onwards, Belgium's population grows at a relatively consistent rate, to more than ten million people the year 2000. Since the turn of the millennium, a positive net migration rate and higher life expectancy has meant that Belgium's population has grown even faster rate than in the twentieth century. Today, Belgium has a very high standard of living, and the capital city of Brussels is home to the headquarters of many international institutions, particularly the European Union.