Osaka is a city in Japan, located at the mouth of the Yodo River on Osaka Bay, in the Kansai region of the main island of Honshu.
The city is the capital of Osaka Prefecture. Osaka was historically the commercial capital of Japan, and to date the heart of Japan's second largest Population of Osaka "city" is next to Yokohama city, but the Osaka Metropolitan area is the 2nd largest in Japan metropolitan area of Osaka-Kobe-Kyoto, whose population is 17,220,000.
A unique title that the city of Osaka holds is the first place in Japan for day to night population ratio of 141%, a depiction of Osaka's economic- and commerce-centric character. While at night time the population ranks third place in the country at 2.6 million, in daytime it surges to 3.7 million, second only after Tokyo.