Hatsushima Island is a man-made island floating in Lake Suwa in central Suwa City, Nagano Prefecture. Created in April 1954 as a launch site for the Lake Suwa Festival Lake Fireworks Display, which continues to be held every summer, the island has become one of the distinctive features of the lake.
Located approximately 250 meters offshore from Lakeside Park on the eastern shore of Lake Suwa, Hatsushima provides a memorable backdrop for the spectacular fireworks that light up the night sky each summer. The island originally covered 495 square meters, but subsequent renovation work expanded its area to approximately 660 square meters.
In 2007, a structure known as the Floating Castle was built on Hatsushima to coincide with the broadcast of the NHK historical drama series Furin Kazan. Inspired by Takashima Castle, the historic castle of Suwa, the structure quickly attracted attention as a new symbol of the island.
The Floating Castle was illuminated at night, creating a fantastical scene over the lake. In July 2008, it was relocated to the rotary in front of Kamisuwa Station, where it was reused as a welcoming monument for visitors to Suwa.
From December 2007 through February 2008, Hatsushima was also transformed by the Winter Fireworks illumination event, part of the Suwa Illuminations Festival. The island was covered in colorful lights, whose reflections shimmered across the surface of Lake Suwa. The event introduced a new winter attraction to the lakeside and created a magical atmosphere during the colder months.
As the island’s facilities and shoreline gradually aged, major renovation work began in fiscal 2008. During the first phase, the western seawall was repaired and collapsed stonework was reconstructed. Safety railings were also installed to protect visitors, while the island was gradually improved as a small park.
The renovation increased the island’s area and helped transform Hatsushima into a more accessible and attractive sightseeing spot. In 2012, four old willow trees that had been planted when the island was originally completed were removed because of their age.
During the second phase of renovation that followed, plans were made to plant new trees and restore a landscape that would harmonize with the surrounding natural environment. In fiscal 2013, repairs to the eastern seawall were completed, successfully recreating the island’s original rounded shape.
A small shrine called Hatsushima Shrine stands on the island. It was established when Hatsushima was completed in 1954, with prayers for the safety of the fireworks display and the protection of Lake Suwa.
The shrine enshrines Suwa Daimyojin, identified with Takeminakata-no-Kami, the principal deity associated with the Suwa region. Today, the shrine is also worshipped as a place associated with safe childbirth and the blessing of children.
One of the most distinctive traditions associated with Hatsushima Shrine is the Onbashira Festival, a major ritual tradition of the Suwa region. Like the shrines of Suwa Taisha, Hatsushima Shrine holds its own Onbashira ceremony.
What makes the ceremony particularly unusual is that the sacred pillars, known as Onbashira, are transported across the lake by boat. The sight of local men pulling the pillars over the water creates a powerful and memorable spectacle, representing the strength of Suwa’s traditional culture and religious heritage.
The maintenance of Hatsushima Shrine is overseen by the Hatsushima Hōsankai, an organization made up of groups connected with Lake Suwa. Every year, local people replace the sacred rope at the shrine’s torii gate and carry out necessary repairs to the shrine buildings.
This community involvement helps preserve the island’s traditions and ensures that the shrine continues to play its role in the cultural life of Lake Suwa.
Traditional protective charms known as Miwatari-mori are also made using wood from old Onbashira pillars after they have been retired. These charms are sold at hotels and souvenir shops around Lake Suwa and are popular keepsakes for visitors.
Hatsushima began simply as an artificial island built to support the launch of fireworks, but over the decades it has developed into a distinctive symbol where local faith, tradition, community life, and the scenery of Lake Suwa come together.
The small island adds a quiet accent to the broad landscape of Lake Suwa throughout the year. On summer nights, it forms part of the dramatic scenery surrounding the fireworks. In winter, it rests quietly amid the cold waters and snow-covered landscape.
Although small in size, Hatsushima offers a glimpse into the close relationship between Lake Suwa and the traditions of the people who have lived around it. From spectacular fireworks to centuries-old religious customs, the island remains a unique cultural landmark floating in the center of the lake.