“Japan's defense ministry said two Chinese guided-missile destroyers and a supply ship had on Monday [June 20] sailed southwest through an area to the southeast of Chiba prefecture,” the Hong Kong-based SCMP quoted from an original report from Kyodo News in Japan.
“They were believed to have been able to enter through the Sea of Japan from the Tsushima Strait and went into the Pacific Ocean via waters near Hokkaido the week prior. The warships sailed into the waters to the east from Miyagi county on the 19th of June and seemed to be traveling around the Japanese archipelago,” according to reports.
China's state-owned Global Times confirmed on June 21 that China's Navy put up a fleet of warships that were sailing around the Japanese archipelago over the past few days.
In detail about the ship's route, the newspaper noted:
It was commanded by the Type 055 massive destroyer Lhasa, the Chinese People's Liberation Army (PLA) Navy flotilla reportedly sailed from the northwest to the south and east sides of Japan on the 20th of June between Monday on Tuesday (June 21) traveling through three important straits close to the island nation and are expected to complete the full circle around Japan should they keep their course and then return to their base.
China's naval exercises near Japan are taking place amid renewed tensions between the two countries regarding Beijing's latest exploration of gas fields in part of the East China Sea near Japan which is being contested by both parties. The Japanese Ministry of Foreign Affairs said on June 20 that they “confirmed that China set up a new drilling facility for gas fields on the west side of a Tokyo-proposed median line separating the two nations' exclusive economic zones in the [East China] sea,” Kyodo News reported on June 23.
Tokyo believes that Beijing's unchecked activity in the dispute zone could cause China to take advantage of underground resources under Japan's side of an unofficial border that divides the territories between the two countries.
Senior diplomats from China and Japan met via teleconference on June 23rd to discuss exploration of the gas field, with Tokyo communicating “strong concern” to Beijing about the issue, Kyodo News reported. The two countries “agreed to keep communicating toward the implementation of the 2008 bilateral agreement on joint gas development in the area” during the discussions, according to the Japanese Foreign Ministry.
Negotiations to define an official line of demarcation that separates Japan and China in the disputable region in the East China Sea have stalled for more than 10 years. The 2008 bilateral agreement, which was referred to by Japan's government on the 23rd of June, stipulates that “both sides will, through joint exploration, select sites for joint development by mutual agreement and conduct joint development at the sites based on the principle of mutual benefit.”
The informal agreement is based on the petroleum resources of an off-shore, well-established gas and oil field in the region, and is located near the disputed Senkaku Islands. Japan has the responsibility of managing the islets without habitation and China claims the islands as its territory because of their strategic position near natural resource reserves and Taiwan, the nation's sovereign state.