Largest Japanese Warship

[Chard]

^^^^ North Korea lobbing test missiles over Japan ...

Japan's invested into ABM systems enough that they can confidently blunt or even negate a North Korea missile attack. Further, the North Koreans know that carrying out such an attack would result in the US leveling everything north of the 38th parallel.

Chinese warships entering Japanese waters ...

Chinese warships operating in Japanese water is also a common occurrence since they're so close. We've invited the Chinese to participate in next year's RIMPAC exercise. Again, China isn't going to do shit because they know the US will respond on Japan's behalf.

South Korean politicians inciting citizens against Japan ... Abe is reactive, not proactive.

Given what Japan has done and continues to do to Korea, I honestly can't blame them. In any case, the US is standing behind them both ready to bop either party upside the head if they threaten to destabilize the region as we've done in the past.

[AiA in Atlanta]

China has never attempted much in overseas expansion but it is firm about what belongs to it: Tibet, Hong Kong ... and islets that Japan currently holds.

[Chard]

China has never attempted much in overseas expansion

Since 1990 they've been expanding their navy and since 2000 they've started getting rather aggressive about the use of Naval assets in a force projection role. Since 1990 the PLAN has expanded their blue water capability with:

1. Bought the Admiral Kuznetsov-class aircraft carrier Varyag in 1998, finally completing refitting in 2011, christened it the Liaoning and is currently undergoing seatrails. Sure, the PLAN doesn't have anywhere near enough aircraft of the right type to give the Liaoning an airgroup, but that's only a matter of time.

Further, now that the PRC knows how to refit a Admiral Kuznetsov-class aircraft carrier they know how to build them, with the PLAN currently considering adding as many as 3 new Liaoning-class ships over the next two decades. Carriers only serve two purposes, using them as mobile air bases to drop bombs on other countries and acting as trip-wires for a nuclear war, so if China isn't looking towards expansion, why are they building one of the requirements for navy expansion?

2. They've built three Type 071 amphibious transport docks and around 74 landing ships in six new classes since 1990. If they aren't interested in overseas expansion then why would they need such a large amphibious landing capability?

3. They build five new classes of guided missile destroyer since 1990, adding fifteen ships to their blue-water navy.

See, you're correct that China has historically never really done much in the way of overseas expansion, but what you're forgetting is that was entirely due to China historically never having much of a naval capability. They're now correcting that deficiency.

And now you know why it is the US keeps such a massively powerful navy.