Nanatsugama, meaning “Seven Pots” or “Seven Caves,” is a spectacular coastal attraction in the northwestern part of Karatsu City, Saga Prefecture. Located within Genkai Quasi-National Park, this remarkable natural formation consists of a series of sea caves carved into towering basalt cliffs by the powerful waves of the Genkai Sea over countless years.
Designated as a National Natural Monument of Japan, Nanatsugama is one of the most impressive geological landscapes along the northern coast of Kyushu. Its rugged cliffs, mysterious caves, unusual rock formations, and deep-blue ocean create a dramatic scene that vividly demonstrates the power of nature.
Although the name suggests that there are exactly seven caves, more than seven openings can actually be found along the approximately 1.5-kilometer stretch of coastline. The caves vary in size and shape, and their dark entrances contrast beautifully with the surrounding blue sea and the geometric patterns of the basalt cliffs.
Visitors can appreciate the scenery from the clifftop walking paths and observation areas or take a sightseeing cruise from nearby Yobuko Port to see the caves from the water. When sea conditions permit, boats can approach the largest cave and enter its interior, offering an extraordinary perspective that cannot be experienced from land.
The greatest attraction of Nanatsugama is its remarkable group of sea caves. They were formed through a long process of coastal erosion, as the powerful waves of the Genkai Sea repeatedly struck and gradually wore away the hard basalt rock.
Over thousands of years, the waves exploited cracks and weaker sections of the rock, gradually enlarging them into deep openings. The resulting caves extend into the cliffs, creating a series of dramatic hollows along the coastline.
The largest cave is located near the center of the formation. It measures approximately 3 meters across at its entrance, about 3 meters in height, and extends roughly 110 meters into the rock. Its narrow entrance gives little indication of the considerable depth hidden within the cliff.
On days when the sea is relatively calm, sightseeing boats can approach the entrance and sometimes travel inside. Once inside, visitors can experience the atmosphere of the cavern, where the sound of waves reverberates against the rock walls and reflected light creates constantly changing patterns on the water and stone surfaces.
The experience offers a striking reminder of the immense natural forces that have shaped this coastline. From outside, the caves appear as dark openings in the sheer cliffs; from the water, their scale and depth become much more apparent.
Another defining feature of Nanatsugama is the striking geometric pattern visible across the cliff faces. These regularly arranged rock formations are known as columnar joints, a geological structure created when molten lava cools and contracts as it solidifies.
As the lava loses heat, it shrinks and develops fractures. These cracks often form polygonal patterns, producing long, column-like sections of rock. Over time, erosion exposes these structures, revealing the remarkable geometric patterns that can be seen along the cliffs at Nanatsugama.
The columnar joints here are particularly well developed. The upper portions of the cliffs feature relatively slender columns, some of which lean or appear broken and irregular. In contrast, the lower sections contain thicker, more orderly columns that extend almost vertically toward the sea.
This difference between the upper and lower rock formations creates an especially distinctive appearance. The cliff faces can look almost as though they were carefully constructed from enormous stone pillars, even though their shapes were produced entirely by geological processes.
The cliffs rise approximately 40 meters above the water, creating a dramatic contrast with the deep-blue Genkai Sea below. The combination of vertical rock formations, dark cave entrances, and the movement of the waves makes Nanatsugama a particularly attractive destination for landscape photography and geological observation.
In addition to the main caves, several unusual rock formations can be seen around Nanatsugama. Their distinctive shapes have inspired local names and become popular points of interest for visitors viewing the coastline from sightseeing boats.
One of the best-known formations is called Elephant’s Nose. When viewed from the sea, the shape of the rock resembles the trunk of an elephant, giving the formation its memorable name.
This unusual appearance is another example of how erosion has created distinctive natural sculptures along the coast. The shape can be appreciated particularly well from the water, making it one of the highlights of the sightseeing cruise.
On the western side of the Nanatsugama area is a curious rock formation known as Megane Iwa, or “Glasses Rock.” Its name comes from the way the rock and its reflection on the surface of the sea resemble a pair of eyeglasses.
The appearance of the formation changes depending on the tide, sunlight, and condition of the water. When the sea is calm, the reflection can make the resemblance particularly striking. This changing scenery gives visitors a different view of the coastline depending on the time of day and weather.
The land above the Nanatsugama cliffs opens into a broad grassy area, where observation points and walking paths allow visitors to enjoy the scenery from above. From the clifftop, the rugged coastline and the deep-blue sea stretch out below, offering an impressive view of the natural formations.
The observation areas provide a different perspective from the sightseeing boats. From above, visitors can appreciate the overall shape of the cliffs and the way the caves have been carved into the coastline. The height of the cliffs and the contrast between the green grassland and the blue sea create excellent opportunities for photography.
Walking along the paths is a pleasant way to explore the area at a relaxed pace. The open grassland provides a peaceful atmosphere, while the nearby cliffs offer a sense of the dramatic coastal landscape.
The waters around Nanatsugama are also known as a favorable fishing area. Anglers are attracted to the coastline because of its rich marine environment. Visitors who enjoy fishing and coastal scenery may find the area particularly appealing.
Whether you are interested in geological formations, landscape photography, walking, or simply enjoying the sea air, the clifftop area provides plenty of opportunities to appreciate Nanatsugama without taking a boat trip.
One of the best ways to appreciate Nanatsugama is to view the caves from the sea. The sightseeing boat Ikamaru, operated from Marinepal Yobuko at Yobuko Port, offers cruises that take passengers close to the dramatic cliffs and sea caves.
The boat is designed in the shape of a squid, reflecting Yobuko’s close association with squid fishing and its famous squid cuisine. Its distinctive appearance makes the cruise an enjoyable sightseeing experience even before reaching the caves.
The cruise takes approximately 40 minutes. During the journey, passengers can enjoy views of the coastline, basalt cliffs, and unusual rock formations from the water. As the boat approaches Nanatsugama, the enormous cave entrances and vertical rock walls become increasingly impressive.
When sea conditions are suitable, the boat may approach and enter the largest cave. This is the highlight of the journey, allowing passengers to experience the interior of a sea cave that extends approximately 110 meters into the cliff.
The sound of the waves, the changing reflections of light, and the enormous rock walls create an atmosphere quite different from the open sea outside. The experience makes it possible to appreciate the depth and scale of the caves in a way that is difficult to imagine from the observation deck alone.
However, entering the caves depends on weather and sea conditions. When waves are too high or the water is unsuitable, the boat may be unable to enter. Visitors should therefore regard cave entry as a possibility rather than a guaranteed part of every cruise.
Marinepal Yobuko is an important sightseeing facility and departure point for marine excursions around Yobuko. It offers visitors opportunities to experience the region’s beautiful coastal environment through different types of sightseeing boats.
In addition to the Ikamaru cruise to Nanatsugama, the facility is associated with Jira, a semi-submarine sightseeing vessel that allows passengers to observe the underwater world. These two experiences offer contrasting ways to appreciate the sea: Ikamaru focuses on dramatic coastal scenery and caves, while Jira provides a view beneath the water’s surface.
The waters around Yobuko are known for their clarity and rich marine ecosystem. The area supports a variety of marine life, making it an appealing destination for visitors interested in the natural environment of the Genkai Sea.
By combining a cruise around Nanatsugama with an underwater observation experience, visitors can discover different aspects of the coastal landscape and marine environment. Marinepal Yobuko is therefore a useful sightseeing base for exploring the natural attractions around Yobuko Port.
Nanatsugama is not only a place of geological interest. The nearby Dojiki Cape is also associated with an old legend connected to Empress Jingu, a legendary figure in early Japanese history.
According to local tradition, Empress Jingu threw earthenware vessels into the sea at this location after returning from a military expedition to Korea. The act is said to have been performed as a prayer or expression of gratitude for victory. The legend is associated with the origin of the place name Dojikizaki, which refers to the earthenware vessels mentioned in the story.
At the northern end of the cape stands Dojizaki Shrine, which is dedicated to Empress Jingu. The small shrine adds a cultural and spiritual dimension to the landscape, allowing visitors to discover the legends and beliefs that have been passed down in the area.
Exploring the cape and shrine alongside the sea caves provides a broader experience of Nanatsugama. The destination brings together the power of nature, local history, and traditional beliefs, revealing another side of Saga Prefecture’s coastal heritage.
Nanatsugama can be enjoyed throughout the year, with the appearance of the sea and cliffs changing according to the weather, sunlight, and season.
On clear days, the deep-blue water creates a beautiful contrast with the dark basalt cliffs. The geometric patterns of the columnar joints become particularly visible under bright sunlight, making this an excellent time for photography and geological observation.
When the sea is calm, the reflections around Megane Rock and the cave entrances can be especially attractive. These conditions are also more favorable for sightseeing boats approaching the caves.
During rough weather, the waves of the Genkai Sea demonstrate the powerful natural forces that created the caves in the first place. Although such conditions can make boat trips difficult or impossible, they also reveal why this coastline has developed such a dramatic landscape over time.
Because Nanatsugama is an exposed coastal area, visitors should pay attention to weather and sea conditions. When walking near the cliffs, it is important to stay on designated paths and observation areas rather than approaching unstable edges.
Nanatsugama is located in the northwestern part of Karatsu City, Saga Prefecture. It can be reached by car or public transportation, although the final section of the journey on foot requires some time when traveling by bus.
From Taku Interchange on the Nagasaki Expressway, the drive takes approximately 60 minutes. The journey from central Karatsu takes approximately 30 minutes, depending on traffic and the route.
A parking area is available near the sightseeing area, making Nanatsugama a convenient destination for visitors traveling by rental car or on a road trip along the northern coast of Saga Prefecture.
From JR Karatsu Station, visitors can take a taxi to Nanatsugama. The journey takes approximately 20 minutes.
Alternatively, take a Showa Bus from Oteguchi Bus Center in central Karatsu on the Minato and Hadoshima route, and get off at Nanatsugama Iriguchi bus stop. The bus journey takes approximately 34 minutes, followed by a walk of about 30 minutes to reach the caves.
Visitors using public transportation should allow sufficient time for the walk from the bus stop and check the bus timetable in advance, as services may be limited depending on the day and time.
Nanatsugama is one of Saga Prefecture’s most remarkable coastal landscapes, where the power of the Genkai Sea has created a spectacular series of caves and cliffs over countless years. Its sea caves, impressive columnar joints, and unusual rock formations make it a fascinating destination for anyone interested in nature and geology.
Visitors can admire the scenery from the observation deck, walk along the grassy clifftop paths, or join the Ikamaru sightseeing cruise from Yobuko to see the caves at close range. When conditions permit, entering the largest cave by boat offers an especially memorable experience.
The surrounding area also contains distinctive rock formations such as Elephant’s Nose and Megane Rock, while the legend of Empress Jingu and the nearby Dojizaki Shrine provide a connection to local history and traditional beliefs.
For travelers exploring Karatsu and Yobuko, Nanatsugama is an outstanding destination where dramatic coastal scenery, geological wonders, marine sightseeing, and regional legends come together. It is well worth including in an itinerary through northern Saga Prefecture.
Free on-site admission
Pleasure Boat
Adults (junior high school students and older) 2000 yen
Children (elementary school students) 1000 yen
Take the “Minato-Yobuko Line” from Otoguchi Bus Center, get off at Nanatsugama Iriguchi bus stop (34 minutes), and walk about 30 minutes from the bus stop.