This chart shows the Countries with smaller population than Tokyo.

Tokyo is huge. It is not really one city, it's more like twenty that all just happen to be next to each other, and that's just the city proper. The Tokyo Metropolitan Area, also known as Greater Tokyo, includes eight prefectures: Tokyo, Chiba, Tochigi, Ibaraki, Saitama, Gunma, Kanagawa and Yamanashi. The total population of the region was estimated to be 37 million by the UN in 2015.

37 million people live in the massive Tokyo-Yokohoma conglomeration. That's a quarter of the population of Japan or 0.52% of all the world's 7.1 billion people. It makes it larger than Canada, over a hundred over countries and in fact the majority of countries in the world.