Lattice Blog

Will Bosi sends ‘Return of the Sleepwalker’ (V17/9A)

Will Bosi has only gone and done it! On February 19th 2024, Will sent ‘Return of the Sleepwalker’ in Las Vegas, USA, becoming the second person to send three V17/9As — the hardest boulder grade in the world!

The line was first established by Daniel Wood in 2021. The ascent took Will 12 sessions in total with 3 sessions on the stand (‘Sleepwalker’ V15/8C) and 9 on the sit (although 2 of the sessions on the sit were quickly abandoned due to rain).

Commenting on the ascent, Will said:

“Coming out to Las Vegas, I had no idea how this trip was going to go as I do not climb on sandstone often and Sleepwalker did not look my style. Sending ‘Sleepwalker’ 8C/V15 in only three days completely blew my mind and having a long time left on the trip, I was pretty confident I could have a good stab at getting ‘Return of the Sleepwalker’ done.

In the last session before the send, everything just clicked. I was feeling confident but as the weather forecast looked bleak with a storm closing in, I was only able to take one rest day before heading back out for another session. I still felt quite tired so I was unsure about even trying it.

However, after warming up, the moves were feeling great and I decided to give it a go. The first attempt went perfectly up to the sloper but then I really messed up the next move through to the slot and almost dropped it. Somehow, I recovered and hit the last hard move perfectly. Pulling onto the slab was incredible and I had to take a minute to get my breath back before heading up to the top”.

This ascent is Will’s third at 9A/V17 after his repeat of Shawn Raboutou’s ‘Alphane’ in Chironico, Switzerland in 2022 and Nalle Hukkataival’s ‘Burden of Dreams’ in Lappnor, Finland in 2023.

The ascent puts Bosi alongside only Simon Lorenzi as climbers who have climbed three 9A/V17 graded boulder problems. Lorenzi climbed ‘Soudain Seul’ in Fontainebleau in 2021, ‘Alphane’ in 2023 and ‘Burden of Dreams’ earlier this year.

But what grade does Will Bosi think ‘Return of the Sleepwalker’ gets?

“Grade wise, I still believe the stand start is only 8C/V15 but I do think the sit start adds enough for it to remain 9A/V17.

In comparison to the other climbs I have done at this grade, I think ‘Return of the Sleepwalker’ comes in around the bottom end of the grade. ‘Burden of Dreams’ was harder but it is such a different style. I think ‘Return [of the Sleepwalker]’ probably came in harder than ‘Alphane’.

Currently, I am very unsure about the distinction between 8C+ and 9A and I think it will take some time and a broader consensus of climbers operating at this level to get the distinction right.”

What is Will Bosi climbing next?

“My next project is dependent on conditions but I would love to head back to Arco and try to finish ‘Excalibur’ (Stefano Ghisolfi’s 9b+/5.15c) or back to Brno to work more on ‘Terranova’. I would also love to spend some time finding new lines in Scotland but the weather seems to always be against that!”.


Will Bosi, 25, is a professional climber from Edinburgh, Scotland. He began his climbing career in competitions, representing Great Britain internationally. Upon retirement from comp climbing, Will turned his focus to outdoor climbing, going on to become one of the best boulderers in the world.

V17/9A is currently the hardest boulder grade in the world. There are only 6 V17/9A that have been established worldwide:

  • ‘Burden of Dreams’, Lappnor, Finland, FA: Nalle Hukkataival
  • ‘Alphane’, Chronico, Switzerland, FA: Shawn Raboutou
  • ‘Megatron’, Eldorado Canyon, USA, FA: Shawn Raboutou
  • ‘Soudain Seul’, Fountainebleau, France, FA: Simon Lorenzi
  • ‘L’Ombre du Voyageur’, France, FA: Charles Albert
  • ‘Return of the Sleepwalker’, Las Vegas, USA, FA: Daniel Woods

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