The government-owned vessels being sent by Beijing to waters around the Japan-controlled but China-claimed Senkaku/Diaoyu Islands are China Coast Guard (CCG) ships, some of which include the service's 10,000-tonne Zhaotou-class cutters.
A Japan Coast Guard (JCG) official in Tokyo told Jane's on 28 January that the CCG usually intrudes into the islands' territorial waters - which extend 12 n miles (22.2 km) - up to three times a month, with the CCG usually deploying four vessels at a time during each intrusion in recent years.
Given that some of the CCG vessels are bigger than even the largest 7,000-tonne ships currently deployed by the JCG, the service usually despatches a higher number of vessels within Japanese territorial waters to respond to every intrusion and drive the Chinese ships away.
The JCG, however, does not normally attempt to drive the CCG ships out of the uninhabited islands' 24 n mile contiguous zone where both Chinese and Taiwanese fishing vessels have been allowed to operate as a result of agreements reached with Tokyo.
Besides Zhaotou-class cutters, two of which are currently in service, other CCG ships known to be used by China to assert territorial claims include Jiangwei I (Type 053 H2G), Tuzhong-, Shucha II-, and Zhaodai-class vessels.
However, no indication has emerged that China has been using part of its fishing fleet as a 'maritime militia' to assert territorial claims in the area, unlike in disputed parts of the South China Sea. Moreover, no People's Liberation Army Navy (PLAN) ships have been seen entering the territorial waters of the Senkaku/Diaoyu Islands.
PLAN assets have, however, been spotted in the contiguous zone. For instance, a PLAN Jiangkai II-class frigate and a Shang (Type 093)-class nuclear-powered attack submarine (SSN) were spotted sailing near the islands in January 2018.
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