Efforts Must Be Made to Convey Their Value to Nation’s History

At the bottom of the seas around the coasts of Japan, as well as the lakes and ponds around the nation, lie legacies that convey the history of the country’s formation and overseas exchanges. Remains and artifacts of historical value must be properly preserved so that they do not deteriorate and can be passed down to future generations.

Underwater historic sites include sunken ships and their cargo and villages submerged by natural disasters. The Cultural Properties Protection Law makes it necessary to preserve such sites when found, as is the case with sites on land.

Found at the Takashima underwater site off the coast of Matsuura, Nagasaki Prefecture, was a warship believed to have sunk in the Kamakura period (late 12th century to 1333) in a tempest during the attempts to conquer Japan, known as the Mongol Invasions of Japan, and stoneware bombs such as those depicted in “Moko Shurai Ekotoba” (Illustrated Account of the Mongol Invasions). Part of the site was designated as a national historic site in 2012, the first for an underwater site in Japan.

The town of Esashi in Hokkaido is using as a tourist resource the salvaged artifacts from the Kaiyo Maru, a warship of the Edo shogunate that ran aground and sank during the Boshin War between forces wanting to keep the shogunate and others seeking a new government under the Meiji Emperor. Visitors likely can feel closer to history by actually seeing the artifacts.

These examples are few and far between, however. Since the end of World War II, research on underwater historic sites has developed mainly in Europe and the United States, with Japan arguably lagging behind.

As of fiscal 2016, only 387 underwater historic sites had been identified nationwide. According to a central government survey, about 80% of local governments have no knowledge of underwater historic sites. First, it is necessary for local governments to grasp the actual situations, in cooperation with local fisheries and port officials.

Reasons why local governments are hesitant to conduct surveys of underwater sites are because of the high cost and technical hurdles involved.

For an underwater site survey, equipment such as sonar and remote-controlled cameras as well as specialized workers with diving skills must be secured. In some cases, surveying an underwater historic site can cost about ¥160,000 per square meter, compared to ¥20,000 per square meter for a historic site on land.

Another issue is the preservation of hulls that remain underwater and the salvaged artifacts.

Wooden vessels left exposed in seawater could possibly be eaten away by organisms. The salvaged artifacts are also susceptible to corrosion when exposed to air.

With limited budgets and staffing, it is difficult for all local governments to undertake such surveys. It would be realistic for each local government to start with what it can do. In order to determine the historical value and conduct the necessary surveys, the support of the central government in terms of both cost and technology is indispensable.

The central government has prepared guidelines that introduce methods for surveying and preserving underwater historic sites as well as advanced initiatives, and it will begin a pilot project within the month to gather and accumulate expertise. Such occasions should also be used to educate local government officials.

It is difficult for the public to see underwater sites directly. Efforts should also be enhanced to take video of sites and artifacts and disseminate them online.

(From The Yomiuri Shimbun, Aug. 6, 2023)