The government said Thursday it had protested to China regarding a set of names recently assigned by Beijing to seabed zones in the East China Sea, including those related to a Japan-administrated group of islets that are also claimed by China.
"There are some names that are based on China's unique assertions regarding the Senkaku Islands," Chief Cabinet Secretary Yoshihide Suga said at a news conference. "Giving names to surrounding seabed topography doesn't change the fact that the Senkakus are our country's inherent territory."
China claims the uninhabited islets, calling them Diaoyu, and its Natural Resources Ministry revealed on Tuesday a list of names for 50 seabed areas in the waters, including three that include the islets as part of them.
The move comes after the municipal assembly in the city of Ishigaki, Okinawa Prefecture, passed a bill Monday to rename an administrative area that includes the Senkaku Islands, which are under its authority, from "Tonoshiro" to "Tonoshiro Senkaku." The change was made to prevent confusion with a locale in downtown Ishigaki, which shares the name “Tonoshiro” with the islands.
Since earlier this year Chinese ships have frequently entered Japanese territorial waters surrounding the Senkakus, ignoring warnings issued by the Japan Coast Guard.