It is the first time since 2012 that leaders of Japan, South Korea and China met and came together to resume their trilateral relations. Their agreement was mainly on economic cooperation.
The meeting was held in Seoul and the leaders attempt to facilitate their relations, which are afflicted with territorial disputes and historical disagreements. Chinese and South Korean leaders agreed on the case that Japan did not do enough to compensate Japanese troops during the Second World War.
The real significance of these talks is the fact that they actually happened, according to BBC's Stephen Evans. Because they were held regularly until three-and-a-half years ago, when they were called off as bad feeling towards Japan had increased.
"We shared the view that trilateral cooperation has been completely restored on the occasion of this summit," Japanese Prime Minister Shinzo Abe, Chinese Premier Li Keqiang South Korean President Park Geun-hye and said in a joint statement.
The three leaders had agreed to work together to finalise the Regional Comprehensive Economic Partnership (RCEP), a 16-nation free trade area favoured by Beijing.
This agreement is also a further step in their goal of the "denuclearization" of North Korea. Japan and South Korea are torn between their allegiance to the US and their need to get along economically with Beijing.
China and South Korea agreed on the matter of increasing their trade, especially through more Korean exports of food to China and co-operation on research into robotics.