, literally meaning "western sea circuit," is a Japanese term denoting both an ancient division of the country and the main road running through it. Saikaido was one of the main circuits

Circuit (subnational entity)

A circuit was a historical political division of China, and is still a Japanese one. In Korea, the same word is translated as "province".- China :...

 of the Gokishichidō

Gokishichido

was the name for ancient administrative units organized in Japan during the Asuka Period , as part of a legal and governmental system borrowed from the Chinese...

 system, which was originally established during the Asuka Period

Asuka period

The , was a period in the history of Japan lasting from 538 to 710 , although its beginning could be said to overlap with the preceding Kofun period...

.

This name identified the geographic region of Kyūshū

Kyushu

is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....

 and the islands of Tsushima

Tsushima Island

Tsushima Island is an island of the Japanese Archipelago situated in the middle of the Tsushima Strait at 34°25'N and 129°20'E. The main island of Tsushima was once a single island, but the island was divided into two in 1671 by the Ōfunakosiseto canal and into three in 1900 by the Manzekiseto canal...

 and Iki

Iki Island

Iki Island is an island lying between the island of Kyūshū and the Tsushima islands in the Tsushima Strait, the eastern channel of the Korea Strait. It is currently part of Nagasaki Prefecture of Japan. The city of Iki is the centre of the local government. The island has three ports.The island’s...

. It consisted of nine ancient provinces and two islands. The provinces included Chikuzen

Chikuzen Province

was an old province of Japan in the area that is today part of Fukuoka Prefecture in Kyūshū. It was sometimes called , with Chikugo Province. Chikuzen bordered Buzen, Bungo, Chikugo, and Hizen Provinces....

, Chikugo

Chikugo Province

is the name of a former province of Japan in the area that is today the southern part of Fukuoka Prefecture on Kyūshū. It was sometimes called , with Chikuzen Province...

, Buzen

Buzen Province

was an old province of Japan in northern Kyūshū in the area of Fukuoka Prefecture and Ōita Prefecture. It was sometimes called , with Bungo Province. Buzen bordered on Bungo and Chikuzen Provinces....

, Bungo

Bungo Province

was a province of Japan in eastern Kyūshū in the area of Ōita Prefecture. It was sometimes called , with Buzen Province. Bungo bordered Buzen, Hyūga, Higo, Chikugo, and Chikuzen Provinces.-History:...

, Hizen

Hizen Province

was an old province of Japan in the area of Saga and Nagasaki prefectures. It was sometimes called , with Higo Province. Hizen bordered on the provinces of Chikuzen and Chikugo. The province was included in Saikaidō...

, Higo

Higo Province

Higo Province was an old province of Japan in the area that is today Kumamoto Prefecture on the island of Kyūshū. It was sometimes called , with Hizen Province. Higo bordered on Chikugo, Bungo, Hyūga, Ōsumi, and Satsuma Provinces....

, Hyūga

Hyuga Province

was an old province of Japan on the east coast of Kyūshū, corresponding to the modern Miyazaki Prefecture. It was sometimes called or . Hyūga bordered on Bungo, Higo, Ōsumi, and Satsuma Province.The ancient capital was near Saito.-Historical record:...

, Satsuma

Satsuma Province

was an old province of Japan that is now the western half of Kagoshima Prefecture on the island of Kyūshū. Its abbreviation is Sasshū .During the Sengoku Period, Satsuma was a fief of the Shimazu daimyo, who ruled much of southern Kyūshū from their castle at Kagoshima city.In 1871, with the...

 and Ōsumi

Osumi Province

was an old province of Japan in the area that is today the eastern part of Kagoshima Prefecture. It was sometimes called . Ōsumi bordered on Hyūga and Satsuma Provinces.Osumi's ancient capital was near modern Kokubu...

.