  We analyze the poset of moves in chip-firing, as defined by Klivans and
Liscio. Answering a question of Propp, we show that the move poset forms the
join-irreducibles of the poset of configurations. The proof involves a graph
augmentation and an analysis of configurations in which only one firing move is
available. We then use this framework to analyze the problem of chip-firing on
a line, where the move poset is relevant to the problem of labeled chip-firing.
