Kumamoto Castle
I've done a lot of castles in Japan, but after the 2016 earthquake, I really had no idea what to expect from Kumamoto-jo. The degree to which the restoration project has seemingly made the castle more accessible to the general public is really impressive.
You can tell something is up when you walk the massive sky bridge from the castle town to the structure itself. When you enter the castle, the amount of modern infrastructure present—from steel beams supporting the stonework to drywall and air conditioning—is a little overwhelming. All-in-all, it's a really cool 2-3 hour diversion, but prepare for a lot of walking!