Blackstone
Brigadier
It is not "enemy at the gates," at all.
The area is in international waters...and it is a busy area, where the US, Japan, S. Korea, and others regularly fly military exercises.
China has decided it wants to monitor this area as an ADIZ to ensure that it knows if any aircraft are flying a threatening flight plan directed at the mainland. If they do, I am sure they will 1st attempt to warn them...if they are far enough out...and then intercept if the do not respond and keep coming and see what they are up to.
If they are not flying toward the mainland, they will just monitor them and leave them alone.
I doubt any of the military aircraft from these other nations will ever file their military exercise flight plans with the PRC.
China's ECS ADIZ highlights the ridiculousness of Shinzo Abe's "no dispute" fantasy, and continues China's efforts to;
1) 'Peace through strength' for domestic and international consumption
2) Increase pressure on Japan
3) Strengthen China-Korea cooperation against Japan (frankly, China doesn't have to work very hard for that)
4) Put Washington in positions where it can't fully back Japan without worsening US-China relations
5) 'Kill the chicken to scare the monkeys' with others in the region
Ian Bremmer, , wrote an article on the , and I think he got it right.