Previously, I talked about Baker’s idea of the “rollercoaster” that is Apocalypse World, whereby “real things, the dice and stats and so on, … give momentum to the fictional things”. I found his description pretty opaque , but managed to summarise it as “real-world actions are triggered from events in the fiction that are potentially interesting, and those actions make those fictional events more interesting”.
Mark Diaz Truman has since refined that a bit for me. He says Baker is talking about explicitly narrative momentum, a kind of energy in running game whereby a story is moving forwards. That doesn’t have to mean “following a pre-written story” ; it just means creating something that the players recognise as a story. As Mark puts it, it manifests as the “sense of making decisions that close doors and open other doors, of moving toward conflicts and decisions instead of just sitting and talking.”
In most games, the work of maintaining this energy lands on the GM, especially outside combat. PbtA rules, by contrast, often create momentum directly. Mark — “the moves themselves generate momentum. Even when you [trigger] a move and “things go smooth” a good move will generate new information and options that will pull you down the path of the story instead of just succeeding or failing on a test.”
In other words, the rules provide opportunities, building blocks, playing pieces, from which the the MC and players can build a story. And they put on pressure, rule out some things, make other seem natural or inevitable. This is often true even on 10+ (or 12+) results — PC successes can still have messy side effects.
As an example, Mark points to the basic move “Escape” from his Urban Shadows: