You’ll love it. I’ve been able to visit twice over the past two years for work and have been able to add on some days to sightsee. Like another poster mentioned definitely try to get down to Kyoto. It’s only a three hour train ride with the Shinkansen. You’ll be pretty close to Himeji castle as well. Think it was 30 minutes from Osaka. So not too far from KyotoI was hoping to do just that mate. I want the full experience, or as close as you can get to that in three weeks anyway.
A couple of the friends I'm traveling with are more clued into the details of how to get about ect as they've been before. Can't wait TBH, I've not looked forward to a holiday like this since I was a kid.