Will Bosi Suggests 5.15a Upgrade to Mutation After First Repeat Since 1998

The FA was by Steve McClure before Bosi was even born. Bosi said it might be harder than 5.15a

Gripped November 2, 2021

Scottish crusher Will Bosi, 22, has made the second ascent of Mutation at Raven Tor in Sheffield, U.K. It was first climbed by Steve McClure (watch below) in 1998 and graded 5.14d.

Bosi suggests it be upgraded to 5.15a, which would make it one of the first 5.15s ever climbed, and the first 5.15 climbed in the U.K. Bosi has spent several days on it over the past four years. The powerful line is the extension to Evolution 5.14c.

Bosi had climbed Evolution in only three goes this summer, and said that the extension is at least 5.14c, so putting a 5.14c on another 5.14c, for Bosi, makes a route much harder than 5.14d. Bosi said that Mutation is at least a 5.15a, but noted that it might be harder, possibly the world’s first 5.15b. The first 5.15b ever climbed was Flex Luther, which recently got an upgrade by Matty Hong, read more about that history-making send here.

Bosi is one of the U.K.’s top sport climbers with a repeat of First Ley 5.15a, the first ascent of Furia de Jabali 5.15b in Spain, and the first ascent of King Capella 5.15c in Spain. At 17, he became the youngest Brit to climb 5.14d at the time with Rainshadow at Malham Cove. Since then, Bosi has become one of the leading lights of GB Climbing. In 2018, he reached the final of IFSC Chamonix Lead Climbing competition which was the first time a male had reached a lead final since 1998. In 2020, Bosi became the first Brit to climb 5.15b abroad with his ascent of La Capella.

We recently spoke to McClure about hard climbing and about how he approaches different projects, he said, “Absolutely case by case. I’m certainly no expert in this field and have a lot to learn. I’ve realized that perhaps the key skill in this kind of climbing is judgment; to know when is the time to try. Too much caution and you’ll never set off, too little, and you could die. I’m very analytical as a climber, and I’m not a really bold climber. I’d say my main strategy is to analyze the danger and realistically be able to decide if its ‘for me’ or not. If I determine the danger is really high, I’ll walk away.”