Scott Christian
Hero
I beg to differ, quite profusely.It is a combination of prepped NPCs, locations, groups, settlements, conflicts, maybe a vague possible future timeline of events in the setting (events like we would have in our own world), improv, extrapolation on existing material, chemistry between what the players choose to do and how the NPCs, monsters and other forces react to that. This isn't an either or situation. Sandboxes involve a lot of different elements to bring them to life.
There is a huge excluded middle in your argument. How rehearsed can it be if I have no idea what is going to happen, yet how can it be only described as improv if I also have prepared materials?
There is no huge middle ground. Every single thing you placed in your sandbox definition can happen in other people's definition of "railroad," "linear," hexcrawl," etc.
Of course there is an interplay between impromptu and rehearsed. I have never see a game where the DM has everything written down. That's because players make choices, and not all choices can be covered. So because the DM didn't write about the campsite on the way to the dungeon, but it was really cool because he made up a bunch of travelling tinkerers camping there. And instead of going to the dungeon, the players helped the tinkerers for a few days. Is this suddenly a sandbox?
It doesn't matter what the answer is becuase both answers are silly: Yes, now they are playing sandbox. No, in order for it to be sandbox it needs this and that.
You either prep or don't. Those are the only two styles that actually exist.