I think you both are confusing the new East China Sea dispute with the old South China Sea dispute, which is over control of the oil rich area surrounding the Spratly Islands, near the Philippines. However, you are both correct, China is flexing its muscles in response to a weakening USA as part of bh0’s mission of ‘fundamental transformation.’
See also the links in my earlier posts, #12 and #17
I work for a big oil US oil company. Senkaku HAS oil it just hasn’t been made public yet and the size of the field has yet to be determined. The Japanese are trying not to tip their hand and the Chi-coms got onto it. As is typical with the Chinese they are both playing chess and trying to lock up oil reserves.