I find the demographics of Japan odd or contrary to European demographics of the time.
Based on the links you gave Japan is equal to France. Considering that Japan is 70% mountains, less than 1/2 of Turkey's land area, 2/3s of France and just came from their bloody Sengoku.
Has this something to do with efficient food production on limited space? or more efficient administration of the Japanese compared to 1600 Europe?
That is why I find ERE ATL below maximum population potential in Anatolia alone.
The Black Death.
Europe lost 50-60% of its population, and France was hit pretty damn hard. Smaller outbreaks persisted well into the 17th century (such as the 1665 outbreak in England which was the last major outbreak in that country) and even before the plague there was a series of famines across the 14th century, with the great famine alone from 1315-17 claiming millions of lives. One plague of note started in 1318, and targeted farm animals, which reduced the amount of protein and vitamin D in the diets of many Europeans and contributed to later famines, but also the devastation of the black death. The plague also kicked off peasant revolts and civil wars were common, France had 9 of them. Peasant revolts, like the Jacquerie in France, the great peasant revolt of 1381 in England, or the Peasant Revolt in 1323 Flanders are emblematic of wide-scale popular uprisings from the 14th through to the 15th centuries, with Germany playing host to apparently at least sixty.
These catastrophic population collapses, mostly from the Black Death and resultant affects of it, crippled Europe's population and set it back 150 years. Europe's population would reach 1300 levels in 1450 but some countries did not recover until much later, with England still having a population of 2.2 million in 1485 when around 1300 it had at least 4 to 5 million, possibly even 6 million. You'll see in that wikipedia article the population of England they give is 4.15 million, a pathetically small amount given its 1300 demographic.
Japan had, well, nothing even remotely like that. Even the Sengoku period was not all that destructive compared to what Europe faced in the middle ages. Apparently the Japanese government instituted a census beginning in 1721, so the most accurate number we have is 26 million people but that was for people who worked for landowners and was collected by temples, estimates put the actual population at around 30 million to account for exempt populations such as monks, travelling merchants, and nobility. This was the Danka System, and it's similar to the Prussian Cantons or English Parishes since affiliation with a Buddhist temple was required by law. It began in 1664 to suppress Christianity but proved very useful to enumerate populations and was standardized in 1671. I don't have those earliest records available to me but apparently there was rapid growth after the end of the Sengoku period because of the political unity and economic activity which transpired. Japan's always had a comparatively large population, just look at it today with 127 million and France with 67 million.
