Self-Defense Force vessels could be deployed to the disputed Senkaku Islands if Chinese military ships enter Japan's territorial waters around the islands, Chief Cabinet Secretary Yoshihide Suga acknowledged at a Jan. 12 news conference.
Moreover, Suga revealed, the government has already signaled to Beijing that Japan is ready to implement such maritime security operations.
Foreign warships entering territorial waters is usually treated as a security "gray area," but the Japanese government has taken a harder line on such incursions of late. Under international maritime law, foreign military vessels are permitted to transit a country's territorial waters as long as they don't present a safety risk -- so-called "innocent passage." However, the Cabinet of Prime Minister Shinzo Abe has passed a decision declaring that Japan will respond to any foreign incursions that do not qualify as innocent passage by announcing a maritime security mobilization, deploying Maritime Self-Defense Force ships and demanding the foreign vessels retire.
"The administration made its concerns known via diplomatic channels in November last year, when a Chinese Navy surveillance vessel sailed repeatedly through waters around the Senkaku Islands" in Okinawa Prefecture, Suga told reporters. Tokyo also made it clear that the ceaseless incursions by Chinese government vessels could trigger maritime security operations by Japan in an attempt to check Chinese moves in the area.
A senior Defense Ministry official told the Mainichi Shimbun that the warning was "connected to confirmation of Japanese sovereignty regarding the Senkaku Islands." The government furthermore sees no signs that China is asserting the incursions constitute "innocent passage," and is prepared to issue a maritime security operations order when Chinese vessels enter the waters around the Senkakus.
In addition to the Chinese surveillance ship's trips into Japanese waters, the Defense Ministry believes that "China Coast Guard vessels that entered Japanese territory in late December "are armed with machine guns and are actually remodeled Chinese Navy frigates," and is stepping up surveillance around the Senkakus.