The big hoo-ha here is that Japan's ruling Liberal Democratic Party vice president, Taro Aso, made a visit to Taiwan and made mention that "the most important thing now is to make sure that war doesn't break out in the Taiwan Strait". China is upset with the whole ordeal and has urged Japan not to rock the boat on this one.
Considering Aso's visit, China is now planning to hold leaders talks with Japan at the ASEAN meeting in Indonesia next month. That's a meeting where the US won't be attending, so it's definitely an opportunity for China to get a word in.
