Originally Posted by
intuition
I guess I've been unlycky, beeing denied reservation upon arrival to KIX, going south. And not just on next train, but all trains that day. Green car, though. Perhaps that's the difference.
I have less experience with the route from Osaka and south, I fly if I go much beyond Osaka.. But on peak travel days, like Obon, it is not unusual for trains to be fully sold out for a couple of days. From Osaka to the soith they run with shorter trains on many departures, so there is less capacity than between Tokyo and Osaka
Green car normally makes it easier, though some of the formations running beyond Osaka have very few green cars, and lower number of reserved cars.