Shikoku

Shikoku ('Four Provinces') takes its name from the provinces into which the island was once divided. The old provinces of Sanuki, Tosa, Iyo and Awa are known today as the prefectures of Kagawa, Kochi, Ehime and Tokushima.
Predominantly rural, Shikoku has everything that the current image of Japan does not: wide open spaces, forests, rural villages and a dramatic natural landscape. However, the island is not just a provincial backwater. There's plenty to see and it's worth devoting at least a week to completing the loop route described below.
The route passes through all four prefectures and includes stops in the capital cities of three of them. Though a number of road bridges have opened in recent years, linking Shikoku with Honshu, the only entry/exit point by rail is across the Inland Sea via the Seto-Ohashi Bridge, opened in 1988

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This route starts in Okayama, taking the Marine Liner train across the bridge to Takamatsu. From here, the route heads south to Kochi via Kotohira. The route continues in a clockwise direction to Uwajima, known for its bull fights and sex museum, then on to Matsuyama, the largest city on the island and a good access point for a visit to Dogo-Onsen, Japan's oldest spa town. The last part of the journey covers the route from Matsuyama back towards Okayama on Honshu.
It's worth noting that though plenty can be accomplished on a rail tour of Shikoku, the more isolated parts of the island, including the two southern capes at Muroto and Ashizuri, can be reached only by infrequent buses or by hiring a car and driving there.
Most weekends between April and September (except possibly in June due to the rainy season), open-air carriages are attached to two of the most scenic rail lines in Shikoku. These carriages are called 'Torocco' and carry an additional charge of ¥310. The first is on the Tokushima line that runs between Awa Ikeda and Tokushima; the open-air carriage is available between Tsuji and Sadamitsu stations, a 45-minute stretch as the line follows Yama-gawa.
The other is on the Yodo line between Kubokawa and Uwajima; an open-air carriage is attached between Tokawa and Ekawasaki. Seat reservations should be made in advance from any JR ticket office.