"But the Ghosthead knew how to tap some of those that might have been. To give them a kind of life. To use them, to push them into the reality that in its very existence denied theirs, which is defined by what happened and by the denial of what did not. Tapped by possibility machines, outcomes that didn’t quite make it to actuality were boosted, and made real.

"If I were to toss a coin, most certain it would land on one side or the other; it’s just possible it might land on its edge. But if I were to make it part of a possibility circuit, I’d turn it into what the Ghosthead would have called a coin of possible falls-a Possible Coin. And if I toss that, things are different.

"One of either heads or tails or just maybe edge will come up as before, and lie there as strong as ever. That’s the fact-coin. And surrounding it, in different degrees of solidity and permanence, depending on how likely they were, are a scattering of its nighs -close possibilities made real. Like ghosts. Some almost as strong as the factual, fading to those that are just barely there. Lying where they would have fallen, heads and tails and a fair few edges. Possibilities, mined and pulled through into the light. Fading as the possibility field shifts.

"This-" He indicated his sword again, seeing Bellis begin to understand. "-is a sword of possible strikes. A Possible Sword. It’s a conductor for a very rare kind of energy. It’s a node in a circuit, a possibility machine. This-" He patted the little pack strapped to his waist. "-is the power: a clockwork engine. These," the wires stitched into his armor, "draw the power up. And the sword completes the circuit. When I grip it, the engine’s whole.

"If the clockwork is running, my arm and the sword mine possibilities. For every factual attack there are a thousand possibilities, nigh-sword ghosts, and all of them strike down together."

Doul sheathed the blade and stared up into the trees’ pitch-black canopy.

"Some of the most likely are very nearly real. Some are fainter than mirages, and their power to cut… is faint. There are countless nigh-blades, of all probabilities, all striking together.

"There’s no martial form I’ve not studied. I’m proficient with most of the weapons I’ve ever encountered, and I can fight without any weapons at all. But what most people don’t know is that I’ve trained with this sword twice. I’ve mastered two kinds of technique.

"This engine… It’s not tight. And it can’t just be wound again, either-there’s more to it than that.