The Shiwaku Islands (塩飽諸島 Shiwakushotō ) or Shiwakujima (塩飽島 ) form an archipelago in the Japanese Inland Sea.
The group is situated between Okayama Prefecture and Kagawa Prefecture in the western Bisan Seto and consists of 28 islands of various sizes. On the Okayama side lie the Kasaoka Islands. The name derives from shioyaku (塩焼く ) or shiowaku (潮湧く ) both meaning boiling seawater to get salt.
Since ancient times, the islands have been an important point for maritime transport.
粟島, part of Mitoyo, populated. In Meiji 30 (1897), the national sailor academy was founded here and subsequently many talented men were send out into the world of shipping industry.
弁天島, part of Marugame, unpopulated.
歩渡島, This island is connected to Hitsuishijima. The name (歩 = walk, 渡 = cross) derives from the fact that it is possible to cross between the islands.
広島, part of Marugame and one of the seven "salt boiling islands". area: 11.66 km², circumference: 18.5 km.
櫃石島, The island takes its name from a megalith in the shape of a chest (jap: 櫃) at its southern part. area: 0.85 km², circumference: 5.4 km, part of Sakaide.
The principal industry on the island is collection of shellfish by diving and trawl fishing.
In mid January the yearly peach festival is held on the compounds of the Ōji-Shrine (王子神社 Ōji-jinja )
本島, part of Marugame, situated in the centre of the Shiwaku Island group. area: 6.74 km², circumference: 16.4 km. It is still the most populous place within the Shiwaku Islands.
Kasajima (笠島 ) - designated as Preservation District of Groups of Traditional Buildings (重要伝統的建造物群保存地区 ) of Japan
岩黒島, part of Sakaide, Kagawa, populated. The Great Seto Bridge passes across this island. area: 0.16 km², circumference: 1.6 km.
The Iwakurojima Interchange on the down-line (away from Tokyo) of the Seto-Chuo Expressway can be used exclusively by islanders by means of a card to unlock the gate.
There is also an emergency phone. Tourists and other people can use an elevator from the bus stop on top of the bridge to access the island.
上真島, part of Marugame, unpopulated.
唐島, part of Mitoyo, unpopulated.
烏小島, part of Marugame, unpopulated.
小裸島, part of Sakaide, unpopulated.
小瀬居島, part of Sakaide, unpopulated.
小与島, part of Sakaide, populated. area: 0.24 km², circumference: 1.3 km.
三つ子島, part of Sakaide, unpopulated. The Great Seto Bridge passes across this island.
室木島, part of Sakaide, unpopulated.
鍋島, part of Sakaide, unpopulated.The Island is connected to Yoshima via a mole. In 1872 a lighthouse constructed by Richard Henry Brunton was erected on the island.
長島, part of Marugame, unpopulated.
二面島, part of Sakaide, unpopulated.
大裸島, part of Sakaide, unpopulated.
小手島, part of Marugame. Popular place for catching Japanese amberjack or Sand lance (Ammodytes personatus).area: 0.6 km², circumference: 3.8 km.
佐柳島, part of Tadotsu. area: 1.83 km², circumference: 6.6 km.
瀬居島,
沙弥島. Due to a land reclamation of the Sakaide Bannosu (番の州 ) industrial area in December 1967, the island became connected to the adjacent land. Adjoining, the island services the Seto Ohashi Memorial Park. In summer the island is crowded by guests who come to bath in the sea. From the Jomon period on the salt making culture developed. At Nakanda beach (ナカンダ浜 nakanda-hama ) earthenware and other finds from that time have been excavated.
The Man'yōshū poet Kakinomoto no Hitomaro paid a visit to the island and composed a tanka and tanka appendage. According to the novelist Nakagawa Yoichi (中河与一 ) from Sakaide, Kakinomoto no Hitomaro had a temple/monument erected on Nakanda beach which in 1936 was moved to its present location on Osogoe beach (オソゴエの浜 ) at (人麻呂岩 ).
On 9 April 2005 the Kagawa Prefectural Higashiyama Kaii Art Museum, housing the collection of Kaii Higashiyama was opened.
下真島, part of Marugame, unpopulated.
白石, part of Marugame, unpopulated.
志々島, part of Mitoyo. area: 0.74 km², circumference: 3.4 km.
高見島, part of Tadotsu, populated. area: 2.33 km², circumference: 6.4 km.
手島, part of Marugame, populated. area: 3.41 km², circumference: 10.9 km.
牛島, part of Marugame, populated. One of seven islands on which salt is extracted from seawater. area: 0.7 km², circumference: 4.2 km.
羽佐島, part of Sakaide, unpopulated.
与島, part of Sakaide and one of the seven "salt boiling islands".
The island is crossed by the Great Seto Bridge and a rest area ("Yoshima parking area") has been built along the highway.
There are in total two parking lots at the rest area. From there the harbour Yoshimakō (与島港 ) in the northern part of the island can be reached. At Yoshimakō there is a Fisherman's Wharf with restaurants and places selling seafood and souvenirs. It is also possible to go with the Japanese warship Kanrin Maru on a sightseeing pleasure cruise of the Great Seto Bridge.
Public-transit buses and authorized islanders can access the island road 274, "Yoshima line", via a personal card. Non-islanders with car may only get as far as the two parking lots as the gate is closed for them. The southern part of the island can be reached by public bus.