According to https://en.wikipedia.org/wiki/List_of_countries_by_population_in_1900 https://en.wikipedia.org/wiki/List_of_countries_by_populatio..., Japan was th

According to https://en.wikipedia.org/wiki/List_of_countries_by_population_in_1900 https://en.wikipedia.org/wiki/List_of_countries_by_populatio..., Japan was the 8th most populous political unit in the world, after China, the British Empire, Russia, France (including colonial possessions), United States, Germany, Austria-Hungary, and the Dutch East Indies. Except for China (questionable) and the Dutch East Indies, those were all considered world powers in their own right. The population of Japan at this point was larger than that of the UK (by 10%), metropolitan France (same), Italy (by 30%), the Ottoman Empire (by 30%), Spain (more than 2x). Going back one more century, to https://en.wikipedia.org/wiki/List_of_countries_by_population_in_1800 https://en.wikipedia.org/wiki/List_of_countries_by_populatio... we see Japan in _6th_ place, after the Qing empire, Maratha Empire, British Empire, French Republic, Russian Empire. Of course in both cases Japan was not a huge part of total world population. It was about 2.5% in 1900 and about 3% in 1800. But that didn't matter when most of the world population wasn't trying to be a world power at all (e.g. they were Chinese peasants). And Japan was more or less comparable to the other major world powers of the time in terms of population. Now productivity is, of course, important: There's a reason the Dutch East Indies were not considered a serious power in 1900 and Japan was. And we can talk about correlation vs causation (e.g. higher productivity might have been enabling more population growth, leading to high-productivity societies becoming more populous). But just in terms of raw numbers, Japan was in fact one of the most populous countries in the world in the 19th century. I agree with your overall point that just adding bodies is not enough. But the premise of the grandparent post was that what works is adding bodied to a _functioning_ economy, which is where the productivity assumption comes in. If you add bodies as fast as you can without hurting your productivity (too much, at least), that's the path to economic success at least in the 19th and early 20th century.