There is this..
First is the economic aspect.
The two countries are faced with uncertainty and risk in the midst of trade friction with the U.S., in particular increasing concerns about a trade war between China and the U.S. that could hurt their own economies as well as those of their major trading partners, including Japan. Strengthening economic ties between Japan and China would benefit both countries. During the summits they shared an understanding of the importance of free trade.
and regarding the political ties, the author rights…
However, if you focus too much on a few sensitive pending issues, you might invite such repercussions as excessive nationalism that could hurt or even destroy the entire relationship. In this regard, it is a minimum but steady achievement that Japan and China agreed to implement a “Maritime and Aerial Communication Mechanism” between their defense authorities to avert unintended clashes between their armed forces in and above nearby water.
The author is Masahiro Kohara and you can read the rest here.