Chinese vessels traveling close to the disputed Senkaku Islands in the East China Sea have begun reissuing data on their locations and routes when in and close to Japanese waters, a source close to the Japan Coast Guard said Saturday.
The change in Chinese vessels' approach appears to be intended to emphasize their administrative right to the Tokyo-controlled Senkakus, which Beijing claims and calls Diaoyu, the source said.
The Chinese vessels are communicating the data using an automatic identification system. Passenger ships and other vessels traveling in international waters are required by a maritime treaty to install the technology aboard.
Japan Coast Guard patrol vessels do not use the technology around the disputed islands to keep their operations confidential.
The source said that Chinese vessels in the vicinity of the Senkaku Islands used to emit AIS signals, but that the practice had ceased in more recent years.
Information conveyed by AIS is publicly available online. The Japan Coast Guard says it limits its own use of the technology to situations such as congested sea routes and marine rescue operations.
The islands continue to be a source of friction for Tokyo and Beijing, which has become increasingly assertive in sending its vessels to the waters around them. On Saturday, the Japan Coast Guard said that Chinese vessels had been spotted in waters near the Senkaku Islands for a 122nd consecutive day.