The Uemachi Plateau (上町台地, うえまちだいち, Uemachi Daichi) is a plateau in

Osaka is a designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the third most populous city in Japan, following Special wards of Tokyo and Yokohama. With a population of 2. ...

City,

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, that extends from the

Osaka Castle is a Japanese castle in Chūō-ku, Osaka, Japan. The castle is one of Japan's most famous landmarks and it played a major role in the unification of Japan during the sixteenth century of the Azuchi-Momoyama period. Layout The main tower ...

and Tenmabashi area to Tennōji in the south.

History and formation

Based on post-war university studies of geological strata and faults, and examination of old maps, it is assumed that by around the 5th century a sandbank had been formed, and that this eventually became the Uemachi Plateau. It is believed that in the

Jōmon period The is the time in Japanese history, traditionally dated between 6,000–300 BCE, during which Japan was inhabited by a diverse hunter-gatherer and early agriculturalist population united through a common Jōmon culture, which reached a c ...

the Uemachi Plateau was a sandbank that separated the

Inland Sea An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large and is either completely surrounded by dry land or connected to an ocean by a river, strait, or "arm of the sea". An inland se ...

to the West from

Kawachi Bay Kawachi Bay (河内湾) was a bay that existed millennia ago in modern Osaka city and surrounds. On its eastern border were the Ikoma mountain range, and the west there was a peninsula where many (pre)historical settlements are found. Both the Yod ...

to the East. Ever since then large amounts of sediment have been deposited from the

Yodo River The , also called the Seta River (瀬田川 ''Seta-gawa'') and the Uji River (宇治川 ''Uji-gawa'') at portions of its route, is the principal river in Osaka Prefecture on Honshu, Japan. The source of the river is Lake Biwa in Shiga Prefectur ...

and the Yamato River. Kawachi Bay turned into Kawachi Lake, then into swampland, and finally into an

alluvial plain An alluvial plain is a largely flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms. A floodplain is part of the process, being the sma ...

. Similarly, due to the movement of the rivers, the western side of the plateau became the plain that is now the center of Osaka City. In contrast to the relatively gentle slope on the eastern side of the plateau, the descent on the western side is steep. This is because of the deposit of large amounts of sediment from the upper reaches of the Yodo and Yamato rivers, which are on the eastern side of the plateau. On the western side of the plateau there are deposits at sea level from

Osaka Bay Osaka Bay (大阪湾 ''Ōsaka-wan'' ) is a bay in western Japan. As an eastern part of the Seto Inland Sea, it is separated from the Pacific Ocean by the Kii Channel and from the neighbor western part of the Inland Sea by the Akashi Strait. ...

. The highest point of the plateau is at the base of the main tower of

, 38 meters above sea level. The names of two wards of Osaka City, Higashinari-ku and

Nishinari-ku is one of the 24 wards of Osaka, Japan. It contains some shopping and entertainment areas, such as Tamade. It lies directly south of the Namba transport hub and extends further south toward Sumiyoshi Park. It is served by the Nankai Railway line ...

, originate from the formation of the Uemachi Plateau. ''Higashinari'' (東成) means "East-becoming" and ''Nishinari'' (西成) means "West-becoming". Plateaus of Japan Landforms of Osaka Prefecture {{Osaka-geo-stub