What Is Shodoshima? Olives, Soy Sauce, Stone and the Sea
This guide is for visitors who want to know what kind of island Shodoshima is before they plan a trip. It covers the island's size and climate, the mountains and gorge, and the industries that shaped it: salt, soy sauce, noodles, sesame oil, stone and olives. It also explains the island's pilgrimage and its link to Osaka Castle.
We used three pages from the Shodoshima Tourism Association, the island's official tourism body, which describe the island, its industry and its history. All pages were read on 2026-10-04. The association's figures for population are from 2017, so treat them as dated.
The island in numbers
The association says Shodoshima is at the center of the Setonaikai National Park. It is the 19th largest island in Japan, with an area of 169.86 square kilometers including more than 20 small islands around it. It gives a population of about 28,000 as of 2017. It says the island is the second largest in the Seto Inland Sea.
Today the island is made up of two towns, Tonosho and Shodoshima. The association says there were 44 villages in the past, which were gradually merged. In 2006 the towns of Uchinomi and Ikeda joined to form Shodoshima Town.
Mountains, gorge and coast
The association says the coast is a ria coast, and that the south coast has a beautiful curved shape. The island is said to look like a cow or a dog facing west. The highest peak is Hoshigajo at 817 meters, which it calls the highest in the Seto Inland Sea. A ridge continues west to the Utsukushigahara highland at 777 meters.
The southern side of this ridge has steep slopes eroded by long years of wind and rain. The association says that erosion made the strange peaks that form the Kankakei gorge. The same page says volcanic activity on the island ran from about 13 million years ago until about one million years ago, and that the base rock is granite.
Climate
The association describes a mild and dry Seto Inland Sea climate. The yearly average temperature is around 15 degrees Celsius. The summer average, from mid-July to early September, is around 26 degrees, with an average high near 31. In January and February the average is around 5 degrees and the average low is about 1 degree. Snow falls once or twice in some years, with little accumulation. Rainfall averages around 1,100 millimeters a year.
Salt, soy sauce and noodles
The association says salt has been made on the island since ancient times. When salt was overproduced in the late Edo period, sailors who carried it to Osaka learned how to brew soy sauce, and the island turned to soy sauce. It says the warm climate suits the yeast, local salt is plentiful, and shipping already existed to carry soybeans and wheat. Farmland is small, which also pushed people toward soy sauce and sea trade.
Tsukudani, foods simmered in soy sauce, grew after the Pacific War. The association says soy sauce makers began making it on 26 September 1945, from sweet potato leaf stalks, with only five workers. It says kelp and seaweed were available from 1946 and the number of makers grew.
It dates hand-stretched somen noodles to 1598, when a villager from Ikeda is said to have learned the technique at Miwa in Yamato on a pilgrimage to Ise. The association says the island's somen is unusual because it is rolled with pure sesame oil. Sesame oil making is dated to 1858.
Stone and Osaka Castle
The association says stone has been quarried here since the Kamakura period, and that Toyoshima stone, a soft dark tuff, comes from Teshima island to the west. Granite from the northern coast became the main stone later. It says Toyotomi Hideyoshi's retainers collected stone on the island for Osaka Castle from 1583. The association says the Tokugawa rebuilding of Osaka Castle from 1620 also used island stone, and that marks on stones left in the quarries match marks on the castle walls today.
Olives
The association says olives were first brought to Kagawa in 1908, when the national agriculture ministry asked three prefectures to try growing them. Only Shodoshima succeeded. It says 519 seedlings were planted on 119 ares, and that a first harvest of 7 kilograms came in 1910. Green olives are picked from late September, and olives for oil from late October into November, when they turn purple and then black-purple.
Pilgrimage and welcome
The island has an 88-temple pilgrimage that the association says was founded in 1686, modeled on the Shikoku pilgrimage. It says the route is about one tenth the length of the Shikoku one and attracts many visitors each year. Islanders traditionally welcome pilgrims with tea, sweets and sweet sake, and the association says this custom of hospitality survives today.
What we could not verify, and therefore left out
- Current population figures newer than 2017.
- Opening hours and fees at museums, the ropeway and the olive park.
- Which shops and makers are open to visitors this season.
- Any ranking of the gorge against others in Japan.
Related guides
Sources
All URLs retrieved 2026-10-04.
- What kind of island is Shodoshima? Basics, terrain and climate (Shodoshima Tourism Association, in Japanese) — (size, mountains, climate)
- What kind of island is Shodoshima? Industry (Shodoshima Tourism Association, in Japanese) — (soy sauce, noodles, stone, olives)
- What kind of island is Shodoshima? History, Osaka Castle, pilgrimage (Shodoshima Tourism Association, in Japanese) — (castle stone, pilgrimage)