Most visitors who make it to Kagawa spend their time cycling Naoshima, eating udon in Takamatsu, and climbing to Kotohira-gu shrine. Those three experiences are genuinely excellent and deserve their reputation. But the prefecture has considerably more to offer once you start looking past the well-documented circuit. The islands scattered across the Seto Inland Sea range from the famous to the nearly unknown. The castles are undervisited even by Japanese standards. The mountain interior of Shodo Island is one of the most dramatic small gorges in the country, seen by a fraction of the visitors who make it to the olive grove. This guide covers what lies beyond the standard itinerary.
Shodo Island — Kankakei Gorge and Somen Culture
Shodo Island is Japan’s second-largest island in the Seto Inland Sea, but it behaves more like a secret than a major destination. While Naoshima draws international art-world attention and regular features in design publications, Shodo Island remains largely the domain of domestic tourists and the occasional well-researched overseas visitor. Its olive groves and olive oil are the primary draw for most visitors, but the island’s interior holds something far more visually dramatic.
Kankakei Gorge
Kankakei is described in Japanese tourism literature as the finest valley landscape in the western part of Japan, a claim that turns out to be accurate rather than promotional. The gorge cuts through the island’s central ridge along a slot of eroded granite that narrows in places to corridors of towering rock. A ropeway (round trip approximately ¥1,500) rises from the valley floor to a ridge-top viewing platform, and a network of hiking trails follows the gorge walls through forest that turns extraordinary shades of red and orange in mid-November.
The gorge is at its most spectacular in the autumn foliage season, but the rock formations and the sense of scale that the narrow valley creates are impressive throughout the year. The hiking trail from the upper ropeway station takes roughly 90 minutes to descend to the valley floor through the gorge — a walk that involves ladders, chain-assisted sections, and several river crossings on flat stones. This is one of the most genuinely adventurous half-day hikes available in Kagawa Prefecture.
Somen Noodle Culture
Shodo Island has been producing hand-stretched somen noodles for over four centuries. The traditional production method, in which noodle strands are repeatedly stretched and twisted over long bamboo poles in the open air, is still practised at small family producers across the island. The production season runs from December through March, when the cold dry air and moderate humidity on the island are exactly suited to hand-stretching without breakage.
Several producers welcome visitors during production season and sell direct from their workshops. Shodo Island somen is considered finer and more delicate than the mass-produced versions widely available on the Japanese mainland, with a silkiness in the finished noodle that reflects the slower, more attentive production method.
Getting to Shodo Island
Ferries from Takamatsu Port to Tonosho take 35 minutes by high-speed ferry (¥800) or 60 minutes by regular ferry (¥690). Ferries also connect with Himeji, Okayama, and Osaka if you are incorporating Shodo Island into a broader Kansai-Shikoku itinerary. Rental cars are available at Tonosho Port and offer the most flexible way to reach Kankakei. Local buses serve the main sites but run infrequently.
Marugame Castle — Japan’s Steepest Stone Walls
Marugame Castle is one of only twelve castles in Japan that retain their original keep, meaning the main tower was never destroyed and rebuilt in modern concrete. That alone makes it historically significant. What makes it architecturally remarkable is the stone wall (ishigaki) on which the keep sits: a layered tier of interlocking granite blocks that climbs from the outer moat to the base of the tower in a slope that at its steepest section reaches approximately 60 degrees — among the most dramatic castle walls in the country.
The Castle and Its Keep
The keep itself is small by castle standards — three stories, wooden interior, accessible via steep interior staircases — but the view from the top takes in the Seto Inland Sea and the islands of Seto-Ohashi bridge to the north, and the Sanuki plain stretching toward the mountains of the Shikoku interior to the south. The experience of standing at the summit of those stone walls, with the keep directly above and the plain far below, is worth the visit regardless of any particular interest in castle architecture.
The castle grounds double as a park used by local residents for morning walks and cherry blossom viewing in early April. Outside the few weeks when the cherry trees attract crowds, it is possible to spend an hour at the castle with very few other people present. Admission to the keep costs ¥200. The grounds are free to enter.
Getting to Marugame
Marugame Station on the JR Yosan Line is approximately 30 minutes from Takamatsu by express (¥570) and 25 minutes from Kotohira by local train. The castle entrance is a 15-minute walk from the station. Marugame is also the location of the founding restaurant of the Marugame Udon chain and has a high density of independent udon shops in the streets around the station — combining a castle visit with an udon crawl in Marugame is a natural full-morning itinerary.
Megijima — The Island of the Oni
Megijima is a small island roughly 20 minutes by ferry from Takamatsu Port (¥720 round trip) that most overseas visitors skip entirely. It should not be skipped. The island’s primary claim on attention is a series of caves cut into the island’s cliffs that are identified in local tradition as the stronghold of the oni — the horned demons of Japanese folklore — from the legend of Momotaro, the Peach Boy who sailed the Seto Inland Sea to defeat them.
The Oni Caves
The cave complex (admission ¥200) is a network of chambers cut into the cliff face on the island’s northern shore. Carved oni figures lurk in alcoves throughout the caves. The combination of low ceilings, dramatic lighting, and the caves' genuine age creates an atmosphere that is genuinely unsettling in a way that staged haunted attractions rarely achieve. The deepest chambers require crouching and give a visceral sense of the caves as shelter rather than spectacle.
Above the caves, a short climb through pine forest reaches a hilltop shrine with a panoramic view over the Seto Inland Sea that is, on clear days, one of the finest unobstructed sea views available from any accessible point in Kagawa. The lighthouse at the island’s northern tip can be reached by a longer trail and adds another hour to the visit.
The island has a very small permanent population, a handful of cafes and small restaurants serving local seafood, and almost no tourist infrastructure. This is precisely what makes it worth visiting.
Zentsuji — Birthplace of Kobo Daishi
Zentsuji is Temple 75 in the Shikoku 88-Temple Pilgrimage and the most historically significant of all 88 temples: it is the birthplace of Kukai, the Buddhist monk who founded Shingon Buddhism in Japan in the ninth century and is known posthumously as Kobo Daishi. The temple complex covers an enormous area by temple standards, with a five-story pagoda, a 500-year-old camphor tree in the inner precinct, and a long corridor of darkness — the Kaidan Meguri — in which pilgrims walk through complete blackness holding a rope, symbolically following the path to spiritual awakening.
The Temple in Practice
The Kaidan Meguri (¥500) is the most visceral experience at Zentsuji and one of the most unusual temple activities available anywhere in Shikoku. The darkness is total. The corridor is long enough that the experience transitions from novelty to something more contemplative, which appears to be the intention. Emerging into the light at the end, by a stone representing the sacred point beneath the main hall, is an effective piece of spiritual theatre whether or not you approach it as a believer.
The five-story pagoda dates from the Edo period and stands in the inner precinct among camphor trees large enough to require four or five people to encircle with linked arms. The temple is active throughout the day with white-robed henro pilgrims completing the 88-temple circuit — seeing the pilgrimage in motion at its most important site gives the centuries-old tradition an immediacy that reading about it cannot produce.
Zentsuji city is served by the Kotoden Kotohira Line from Takamatsu (approximately 60 minutes, ¥550) or by JR from Kotohira in about 10 minutes. The temple entrance is a 10-minute walk from Zentsuji Station.
Takara Island and Uninhabited Beaches
The outer islands of the Seto Inland Sea extend well beyond Naoshima and Shodo Island into territory that sees almost no overseas visitors. The island of Takara — known in Japanese as Takarajima — is among the more remote options accessible by ferry from the Kagawa coast, and offers beaches of the kind that appear in travel writing as “undiscovered” because they genuinely are.
Access requires more planning than a standard day trip. Ferries from Takamatsu operate on limited schedules to the outer islands, and the logistics require checking current timetables and booking accommodation in advance at the handful of minshuku guesthouses operating on the island. For visitors with two or three days of flexibility in their Kagawa schedule and a strong preference for uninhabited coastline over museum queues, the outer islands represent a genuinely different side of the prefecture.
Practical Tips
Combining hidden gems: Marugame Castle and Zentsuji sit on the same JR and Kotoden rail corridor between Takamatsu and Kotohira, making them natural companions on a single day with Kotohira-gu as the endpoint. Megijima and Shodo Island are separate day trips by ferry from Takamatsu Port, though a very early start could theoretically reach Megijima for the morning and return to Takamatsu by early afternoon.
Season for Kankakei: Mid-November is the peak of autumn foliage in the gorge and the single most atmospheric time to visit. Accommodation on Shodo Island during this period should be booked weeks in advance. The ropeway operates year-round except during high winds and maintenance periods.