William Bosi

In 2016, Bosi came to attention when aged 17 he redpointed Steve McClure's famous British sport climbing route Rainshadow, becoming the youngest Briton to climb a 9a (5.14d) graded sport route.[2][3]

In 2020–2021, Bosi became only the second British climber in history, after Steve McClure, to climb a 9b (5.15b) grade sport route with his repeat of Adam Ondra's La Capella, and followed up by his first free ascent of King Capella (a route initially considered a possible 9b+), both of which are in Siurana in Spain.[4]

In 2022, on a trip with Adam Ondra to his home crag of Moravský Kras in the Czech Republic, Bosi flashed the 8B+ (V14) boulder, Charizard (he failed on Ondra's as yet unrepeated 8C+ boulder, Terranova).[5] That year, he also created Honey Badger in the English peak district, which he graded at 8C+ (V16).[6][7]

In 2022, Bosi became one of only a handful of boulderers in the world to have climbed a grade V17 (9A) boulder when he repeated Shawn Raboutou's Alphane. In 2023, he made the only repeat of Nalle Hukkataival's Burden of Dreams, considered the world's first-ever V17 (9A) boulder, and which at the time of Bosi's repeat was still considered the world's hardest boulder.[8][9][10]

Bosi has represented Britain in competition lead climbing, in both youth and adult formats, and in 2018 became the first Briton to reach an International Federation of Sport Climbing (IFSC) final in 30 years, where he finished fifth at the IFSC World Cup in Chamonix; he finished fourth twice during the 2019 IFSC World Cup.[11][12] Bosi narrowly missed out on a place in the Tokyo 2020 Olympics, despite trying to learn speed climbing, a required discipline in Olympic competition climbing.[13]

In 2021, Bosi announced that he was taking a break from competition climbing to focus on outdoor sport climbing and bouldering.[5]

9b (5.15b):

• King Capella – Siurana (ESP) – March, 2021. First ascent, which Bosi felt was at 9b+,[4][14] but the grade was settled at 9b after repeats by Alex Megos (2021), and Jakob Schubert (2021).[15][16]

• La Capella – Siurana (ESP) – February, 2020. Third repeat of Adam Ondra's 2011 route, and the second-ever British climber to climb a 9b route (after Steve McClure with Rainman in 2017); sometimes considered closer to 9a+.[17]

9a+ (5.15a):

• Free at Last – Dumbarton Rock (GBR) – July, 2022. First ascent. A long-standing unsolved line beside Dave Cuthbertson's famous 1983 route, Requiem (E8 6c), and Dave MacLeod's 2006 equally notable route, Rhapsody (E11 7a); Free at Last became Scotland's hardest route.[18][19]

• Brandenburg Gate – Raven Tor (GBR) – November, 2021. First ascent. The line was regarded as a "holy grail" of British sport climbing.[20]

• Mutation – Raven Tor (GBR) – October, 2021. First repeat of Steve McClure's ground-breaking 1998 route, which Bosi suggested was "at least" 9a+ (and possibly harder), making it one of the first-ever 9a+ sport climbing routes in history.[21][22][23]

• First Ley – Margalef (ESP) – February, 2021. Repeat ascent of Chris Sharma's 2010 route that is popular with aspiring 9a+ climbers.[22]

• La Furia de Jabalí – Siurana (ESP) – February, 2021. First ascent, which Bosi felt could be 9b, but the grade later settled at 9a+ after repeats by Alex Megos (2021), Jakob Schubert (2021), and Adam Ondra (2022).[4]

9a (5.14d):

• Rainshadow – Malham Cove (GBR) – May, 2016. Became the youngest Briton to climb at 9a when he made the fifth repeat of Steve McClure's iconic 2003 route, aged 17; Rainshadow is considered the "benchmark" for aspiring 9a sport climbers in Britain.[2][3][24]

V17 (9A):

• Burden of Dreams – Lappnor, (FIN) – April, 2023. First repeat of the world's first-ever V17 boulder problem by Nalle Hukkataival (2016), and in 2023, was still considered the world's hardest boulder;[8][25] Bosi practiced on a replica 3D version in Britain.[9][10][26]

• Alphane – Chironico, (SUI) – November, 2022. Second repeat of Shawn Raboutou's route that Bosi felt was easier than Honey Badger.[27][28]

V16 (8C+):

• Ephyra – Chironico, (SUI) – November, 2022. Third repeat of Jimmy Webb's 2019 boulder.[29]

• Honey Badger – Peak District, (GBR) – August, 2022. First ascent and the third British boulder to be graded at V16.[6][7]

V15 (8C):

• Dreamtime – Cresciano, (SUI) – December, 2022. Repeat of the famous boulder Fred Nicole route; took only 4 attempts.[30][31]