Lake Jinzai is a beautiful brackish lake in western Izumo City, Shimane Prefecture. Mentioned in the ancient chronicle Izumo no Kuni Fudoki, compiled in the 8th century, the lake is a scenic destination where the natural landscape and ancient traditions of Izumo come together.
With a circumference of approximately 5.3 kilometers, Lake Jinzai is relatively compact, making it an enjoyable place to explore at a relaxed pace. The lakeshore is surrounded by abundant vegetation, including reeds and cattails, while Mount Sanbe rises in the distance to the southwest. The scenery changes beautifully with the seasons.
Lake Jinzai is also connected to the Sea of Japan through the Sakai River. Because seawater and freshwater mix in the lake, it provides a rich environment for a wide variety of aquatic life.
Lake Jinzai is particularly well known for its high-quality Yamato shijimi freshwater clams. The lake has long supported a thriving fishing industry, and its annual clam harvest is reported to reach approximately 17,000 tons.
The lake’s productivity is closely connected to its brackish environment. The mixture of seawater and freshwater creates favorable conditions for shijimi clams to grow.
In addition to clams, the lake is home to a variety of fish and other aquatic species, including eels, carp, crucian carp, and mullet. The combination of freshwater and marine environments makes Lake Jinzai an especially interesting destination for visitors who enjoy nature and local food culture.
Lake Jinzai is also a rewarding destination for birdwatchers. Approximately 100 species of wild birds can be observed around the lake throughout the year.
Depending on the season, visitors may see waterfowl such as swans, spot-billed ducks, and common pochards resting or feeding on the lake. A birdwatching shelter has been established along the lakeshore, making it possible for both beginners and experienced birdwatchers to enjoy observing the wildlife.
The lake’s brackish waters support both freshwater and marine fish. More than 70 species of fish have been recorded in the area, highlighting the remarkable diversity of its aquatic ecosystem.
The area around Lake Jinzai is closely associated with the mythology of ancient Izumo. According to local tradition, it is the birthplace of Suseribime-no-Mikoto, a daughter of Susanoo-no-Mikoto and the wife of Okuninushi-no-Mikoto in Japanese mythology.
A historic site known as Iwatsubo is said to be associated with the place where Suseribime-no-Mikoto was given her first bath as a newborn. The tradition adds a strong mythical dimension to the landscape around the lake.
The name Jinzai itself is traditionally said to be connected with meanings such as “a place where the gods reside” or “the wife of a deity.” Nearby Naesa Shrine provides another opportunity to explore the area’s connection with ancient Izumo traditions while walking through the surrounding landscape.
The origins of Lake Jinzai can be traced back to the distant past. During the Jomon period, the area was part of a large bay connected to the Sea of Japan.
Over time, sediment carried by the Hii River and Kando River gradually filled the bay. The area eventually became divided into eastern and western sections. The eastern section developed into what is now Lake Shinji, while the western section became Lake Jinzai.
During the Yayoi period, the lake became separated from the open sea while retaining a brackish environment. Later, during the Edo period, river improvement projects and land reclamation further shaped the lake into its present form.
In particular, the construction of the Sakai River channel helped regulate the lake’s water level and improve drainage, contributing to the stable environment seen today.
Lake Jinzai has also been appreciated as a place of scenic beauty for centuries. During the middle of the Edo period, a collection known as the “Nine Views of Lake Jinzai” was created.
Inspired by the famous Eight Views of Omi around Lake Biwa, these scenic views were depicted by the Kyoto-based painter Hagura Kotei. The paintings captured the beauty of the lake and its surrounding landscape from an artistic perspective.
Some of these works can still be seen today at places such as the Izumo Mingeikan, allowing visitors to appreciate Lake Jinzai from both historical and artistic perspectives.
Lake Jinzai offers a different atmosphere in every season. In spring, fresh green foliage is reflected on the calm surface of the lake. Summer brings the Lake Jinzai Fireworks Festival, when approximately 2,000 fireworks illuminate the night sky and shimmer across the water.
In autumn, the surrounding landscape takes on warm colors as the foliage changes, while winter brings migratory birds that gather around the quiet lake.
The lake also offers opportunities for fishing and sightseeing cruises. On the sightseeing boat Shinseimaru, visitors can enjoy views of the lake while tasting seasonal local dishes, creating a relaxing way to experience the area’s scenery and cuisine.
On the western shore of Lake Jinzai, visitors can find Koryo Onsen, a hot-spring area where day visitors can enjoy bathing and accommodation facilities are also available.
After relaxing in the hot springs surrounded by nature, a walk along the approximately 2.5-kilometer lakeside walking route is a pleasant way to explore the area.
Along the way, visitors can observe aquatic plants, wild birds, fish, and other wildlife while enjoying the peaceful atmosphere of the lake.
Lake Jinzai is a fascinating destination where the natural environment, local fishing culture, ancient history, and Izumo mythology come together.
Its reputation as a shijimi clam-producing area is only one part of its appeal. The lake’s diverse ecosystem, seasonal scenery, ancient legends, artistic heritage, and recreational opportunities offer many different ways to enjoy a visit.
For travelers exploring Izumo, a visit to Lake Jinzai provides a chance to step away from the city’s better-known attractions and experience a quieter side of the region. Take a leisurely walk along the lakeshore, watch birds on the water, enjoy local seafood, or simply admire the scenery while imagining the ancient landscape described in Izumo’s myths.