Japan has less land area as California... and 140 million people. Also to note that they have a sizable percentage of land held as reserve forests in Japan, so the population is even more dense than the above comparison would indicate.
The thought of that many people in such a small area actually makes me uncomfortable. Prince Edward Island is our most densely populated province and Toronto's population is twice as much as all Atlantic provinces ( of which P.E.I is one ) combined. I think that speaks to the vast emptiness of the rest of the province. That Ontario can have one city with twice the population of all Atlantic provinces combined but still not be as densely populated as one little Atlantic province.
Welcome to Hong Kong. Go watch videos of the population density there as a way to get over that phobia. Hong Kong is about 1/7 the size of PEI, but has 1/3 the population of Canada as a whole. Singapore is even worse.The land population density as at mid-2014 stood at 6 690 persons per square kilometre.