TheSan'yō Region (山陽地方San'yō-chihō) is an area in the south ofHonshū, the main island ofJapan.[1][2] It consists of the southern part of theChūgoku region, facing theSeto Inland Sea. The nameSan'yō means "southern, sunny (yō) side of the mountains" and contrasts with theSan'in or "northern, shady (in) side of the mountains".
The region is generally considered to include the prefectures ofOkayama,Hiroshima andYamaguchi. Sometimes, the section ofHyōgo Prefecture that formerly comprisedHarima Province is considered to be within the region as well.
TheSan'yō encompasses the pre-Meiji provincial areas ofHarima,Mimasaka,Bizen,Bitchu,Bingo,Aki,Suō andNagato.[3]
The region is served by theSan'yō Main Line andSanyō Shinkansen.
The San'in subregion is a subregion ofChūgoku region that composes of the prefectures of Shimane, Tottori, and sometimes the northern portion of Yamaguchi Prefecture. The northern portion of Yamaguchi Prefecture composes ofAbu,Hagi, andNagato. The San'yo subregion is a subregion ofChūgoku region and is composed of the prefectures of Hiroshima, Okayama, and Yamaguchi in its entirety.
Per Japanese census data,[4] and,[5] the San'yo subregion has had positive population growth throughout the 20th century and negative population growth since the beginning of 21st century.
| Year | Pop. | ±% |
|---|---|---|
| 1920 | 3,801,000 | — |
| 1930 | 4,112,136 | +8.2% |
| 1940 | 4,492,504 | +9.2% |
| 1950 | 5,283,967 | +17.6% |
| 1960 | 5,456,043 | +3.3% |
| 1970 | 5,654,135 | +3.6% |
| 1980 | 6,197,161 | +9.6% |
| 1990 | 6,348,847 | +2.4% |
| 2000 | 6,357,707 | +0.1% |
| 2010 | 6,257,364 | −1.6% |
| 2020 | 6,079,644 | −2.8% |
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 | This Hiroshima Prefecture location article is astub. You can help Wikipedia byexpanding it. |
 | This Okayama Prefecture location article is astub. You can help Wikipedia byexpanding it. |
 | This article about a location in Yamaguchi Prefecture is astub. You can help Wikipedia byexpanding it. |
