The Japanese and Chinese governments have agreed that the bilateral maritime liaison mechanism will not be employed in situations involving territorial waters and territorial airspace.
The two governments will stipulate the exclusion in a written agreement and aim to start operating the mechanism this summer at the earliest.
The mechanism is being set up as an emergency contact system between the two governments to prevent accidental clashes between the Self-Defence Forces and the Chinese military.
The two sides decided to set aside China's territorial claims over the Senkaku Islands in Okinawa Prefecture to reach an early agreement on establishing the mechanism.
If Chinese forces enter Japanese territorial waters or airspace, Japan would immediately respond based on domestic law, such as by ordering seaborne patrol actions or scrambling fighter jets to warn Chinese military planes.
The liaison mechanism will be defined as a system to secure sufficient communication between both countries before such responses are called for.
The mechanism will be operated mainly when there are situations in the exclusive economic zones - which are within 200 nautical miles (about 370 kilometers) from shores - and in the air defence identification zones (ADIZs, see below) over high seas and near territorial airspace.
Some in the Japanese government voiced their concern that if the maritime liaison mechanism covers territorial waters and territorial airspace, the Chinese may use the mechanism in their favour by, for example, contacting an Air Self-Defence Force aircraft near the Senkaku Islands to demonstrate China's claims of the islands.
In January, defence officials from both sides gathered to resume talks on setting up the maritime liaison mechanism for the first time in 2½ years.
The written agreement will likely include such measures as installing hotlines to connect chiefs of staff of the Maritime Self-Defence Force and the ASDF, and their counterparts from China.
The agreement will also stipulate telecommunications procedures when vessels and aircraft of the two sides approach each other.
In January 2013, on the high seas of the East China Sea, a Chinese military vessel locked the radar of its fire control system on an MSDF destroyer. In November 2013, China unilaterally set an ADIZ, which partially overlaps that of Japan.
In May and June of 2014, Chinese military planes repeatedly came abnormally close to SDF aircraft. Because of such incidents in the past, there are fears over accidental clashes between the SDF and the Chinese military.