Earlier quoted context omitted.
What? No. I live in Japan and you absolutely do not need to book trains in advance, ever, for any reason. It's a good idea if you're planning to travel during peak hours on the first and last days of a major holiday period, but there is a free seating area that you can ride. The only downside is that you may need to wait a bit on the platform until you're squeezed onto the shinkansen. You're sacrificing some comfort…
> But that problem only occurs 3 weeks out of an entire year. Which is, of course, when you're statistically the most likely to be traveling. And the fact that a ticket is valid the whole day doesn't help much when your flight is delayed overnight or by a day. Some people tend to travel precisely when others are not, and might not run into this problem, seems like that might be your case. Other people travel precisel…
If you book in advance and your plane is delayed by a whole day, your ticket is void. That's it. You're done.
...In which case you can just show up to the station and buy an unreserved ticket and ride, like everybody else and like I mentioned is the better idea.
My point is that reserving in advance has no purpose because of reasons you're giving to somehow justify it. If you don't book in advance, there is zero chance of missing your train due to a delayed flight since you're buying it 5 minutes before riding.
You seem very, very confused.