Kaka-no-Kukedo Sea Caves

Kaka-no-Kukedo is a pair of great sea caves carved into the rugged north coast of the Shimane Peninsula, near the fishing harbour of Kaka in the Shimane-cho district of Matsue. This is the wildest stretch of the peninsula, all jagged inlets, sheer cliffs and wave-worn islets of volcanic rock, and it lies within Daisen-Oki National Park. The two caves, known as New Kukedo and Old Kukedo, can only be reached from the water, so a visit means boarding one of the sightseeing boats that set out from Kaka Harbour.

The headline sight is the New Kukedo (Shin-Kukedo), an enormous tunnel-like cavern with three openings that the boat glides right through. It measures roughly two hundred metres in length and around forty metres high, and when the midday sun angles into the entrances the seawater lights up in luminous shades of emerald and jade. The play of light on the water and the walls, framed by the dark rock of the cave, is the reason the tour has drawn visitors for generations.

Old Kukedo (Kyu-Kukedo) is a quieter, more solemn place. Long associated with Shinto and Buddhist belief, it is tied to legends of Jizo, the protector of children, and to a myth recorded in the eighth-century Izumo-no-Kuni Fudoki naming this coast as the birthplace of Sada-no-Okami, the guardian deity of the Shimane Peninsula who is enshrined at nearby Sada Shrine. Small stone offerings and a sense of the sacred linger in the sea cave's shadows, giving the excursion a layer of folklore alongside the natural spectacle.

The experience is gentle and accessible for most visitors: you board at the Marine Plaza landing, and the guided boat ride typically lasts around fifty minutes, threading between rocky islets before entering the caves. Because everything happens afloat, there is no strenuous walking, though the schedule depends on the season and the weather, and tours are suspended when the sea is rough. Bring a light layer, as it is cool and breezy out on the water even in summer.

The best conditions are a calm, bright day, ideally around midday when the sun reaches deepest into the New Kukedo and the emerald effect is strongest. Late spring through autumn offers the most reliable sailings; winter seas on this exposed coast are often too heavy for the boats to run.

Getting to Kaka without a car takes patience. From JR Matsue Station you can take an Ichibata bus heading out onto the Shimane Peninsula toward Shimane-cho and Kaka, alighting near the harbour where the boats depart. Driving is easier, about forty minutes from central Matsue over the peninsula's hills to the little port. Either way, Kaka-no-Kukedo rewards the effort with a coastline few travellers see and a boat ride that combines raw sea scenery with some of Izumo's oldest legends.