Will Bosi is a strong boulderer from Scotland. 9A/V17 is the hardest boulder grade so far. At present there are 5 boulders graded 9A:

• Burden of Dreams

• Return of the Sleepwalker

• Alphane

• Megatron

• L'Ombre du Voyageur

Will Bosi has climbed 3 of these, most recently Return of the Sleepwalker.

The gist of this question is whether Bosi will "complete" the set of 9As in the world before people add more to the list. You can think of it as trying to distinguish between a couple of possible worlds:

• Strong Bosi world: Bosi is able to complete the hardest climbs faster than other climbers can find them

• Many strong climbers world: The number of boulderers strong enough to climb 9A only keeps increasing, and they put up boulders faster and faster, and Bosi is just one of many and has no hope of keeping up.

If at any time there are eight 9A boulders that Bosi has not done, this market resolves NO. (We use this as a proxy for "number of boulders is growing faster than he can keep up.) If at any time he has climbed all the 9A boulders in the world, market resolves YES. Otherwise, market remains open and close date will be extended as necessary.

A boulder "proposed" 9A (i.e. only one climber has climbed it) counts, as long as the general consensus is that it was a serious grading by a strong climber. If there is significant controversy I will do my best to defer to expert opinion in a fair way. Because there's this element of subjectivity, I won't bet.