Japan Institute for National Fundamentals

　　　　　　On July 14, the Defense Ministry said five Chinese naval ships sailed through the Soya Strait off Hokkaido. Russian military ships have frequently passed the strait. In June, two Chinese naval ships passed through the Osumi Strait in Kagoshima Prefecture. I have a sense of crisis about the vulnerability of Japan's control over waters, particularly over straits.

Unreasonable abandonment of territorial waters
　　　　　　Japan has set a limit of territorial waters at 12 nautical miles (about 22 kilometers) from the coastal baseline, exercising sovereignty over the coastal waters. At five straits -- the Soya Strait, the Tsugaru Strait (between Aomori Prefecture and Hokkaido), the Osumi Strait, and the Tsushima Strait Western and Eastern Channels (in Nagasaki Prefecture), however, Japan has limited territorial waters at 3 nautical miles (about 5.6 kilometers), abandoning its jurisdiction on the central portions of these straits and treating them as high seas.
　　　　　　The United Nations Convention on the Law of the Sea designates straits for international navigation as "international straits" where the right of passage is given to ships, submerged submarines and aircraft. In international straits within territorial waters, however, unapproved foreign marine surveys, demonstrations and stays without special reasons are banned under UNCLOS. The "traffic separation zone" designating sea lanes can be established for strict navigation control.
　　　　　　At the five straits, however, Japan has voluntarily abandoned territorial waters irrespective of UNCLOS provisions. Japan thus falls short of imposing restrictions on the passage of foreign military ships through the five straits or having law enforcement authority over civilian ships in the straits. It fails even to conduct crime prevention operations. The government has explained that it has designated the five straits as special waters to guarantee free international traffic. But this reasoning is illogical. The special water designation is generally interpreted as designed to allow nuclear-armed ships to pass through the straits even under Japan's non-nuclear three principles.

Maritime security leads to nation's security
　　　　　　Here is an overseas case. At the Strait of Malacca, an international strait through which more than 90,000 ships pass annually, the three coastal countries of Indonesia, Malaysia and Singapore have not abandoned territorial waters. Rather, they have incorporated Malacca waters into their respective territorial waters for navigation control and other maritime safety measures as massive ship traffic has made the strait vulnerable to accidents and incidents.
　　　　　　Japan should promptly abolish the special waters, set the 12-nautical mile territorial waters at the five straits and discontinue their designation as international straits. Under international standards, the Osumi Strait and the Tsushima Strait Eastern Channel do not have to be designated as international straits because nearby alternative sea lanes for international navigation are available. Japan may call for enhancing control on the Soya Strait at talks with Russia at the other side of the strait. It may make a similar request regarding the Tsushima Strait Western Channel at talks with South Korea. The treatment of the Tsugaru Strait is important. If the Tsugaru Strait is to be designated as an international strait, Japan may have to build passage control arrangements by designating sea lanes for safe navigation purposes.　　　
　　　　　　Based on the fact that not only the American but also the Chinese and Russian military ships pass through the straits to and from the Sea of Japan, the Japanese government must strictly control the passage. In Japan, maritime security directly leads to the nation’s security.
　
Yoshihiko Yamada is Director, Japan Institute for National Fundamentals, and Professor at Tokai University.