Next to Osaka Prefecture, there are two historical cities, Nara and Kyoto. Until the capital was transferred to Tokyo in 1868, these cities were capital cities of Japan. (Previously, the capital had moved to the palace of whichever emperor was reigning.) In 710 A.D., the capital city of Heijo-kyo (Nara city) was built, and many temples were transferred to, and constructed at Heijo-kyo. In 794 A.D., the capital was transferred to Heian-kyo (Kyoto city), and the city flourished as the seat of Japan's imperial court for over 1,000 years. These cities are being blessed with a great variety of historical, cultural heritage, including temples, shrines, and a castle which are recognized by UNESCO as World Cultural Heritages.

Sakai is famous for Emperor Nintoku's Mausoleum, which is the largest toumbs in the world.

With a population of more than 800,000, Sakai is the 2nd largest city in Osaka Prefecture, and 13th largest city in Japan. Sakai made new start as a "core urban city" in April 1996, and aims to make a tangible and positive contribution to community-building.
Sakai has developed as a fishing port during the Kamakura Period, and later as a sea transport center for western Japan. During the Sengoku Period (Age of Civil Wars), Sakai served as a trading port, handling the overseas trade from Ming Dynasty China, Portugal and Spain. At that time, Sakai developed as a unique moat-surrounded town, and flourished as an autonomous city.

Osaka Prefecture, located at the approximate center of Japan, is the second smallest prefecture in Japan. The area is only 0.5%(approximately 1,890 square kilometers) of the nation's entire land area, but it has 7%(8.8 million) of the entire population. So, it's making Osaka the second most populous prefecture after Tokyo. Furthermore, of all foreigners registered in Japan, 15.6%(approximately 210,000 foreigners) reside in Osaka.