Comparative Provocation

One of the issues that kept coming up in the weeklong visit to Japan is the Senkaku islands dispute.  Japan has them, China wants them.  What puzzles me is Japan's military stance.  One of the questions I have been asking lately for pretty much everyone is that China and Russia are not the only actors that can play the anti-access/area denial game of developing weapons (anti-air and anti-ship missiles, subs, etc). 

If China is threatening these islands, why not put some defenses in place that would raise the costs of an attack--to create some deterrence? The answer? This would be too provocative.

So, what is Japan doing?  It is building up its capacity to take back the islands if the Chinese take them. This means aircraft carriers that are not called such things and amphibious ships to land troops.  There are two problems with this:

1. Folks in the neighborhood might just be provoked bigtime but Japan developing these capabilities.  
2. Trying to take back lost territory is far likelier to cause a dispute to escalate than placing some weapons.  The scenario would play out thusly: China takes some islands and then tells Japan if you try to take them back, we will escalate.  Um and then what?

So, I am confused.  Perhaps Japan has only lousy choices from which to choose, but the choice of developing the ability to project power via helicopter carriers and amphib stuff seems the most problematic.  What say you?