Japanese bouldering and trad climbing phenomenon Toru Nakajima recently made the first free solo ascent of Japan's highest waterfall, Shomyo Falls (350m) in Toyama. Sawanobori is the Japanese art of climbing a mountain river to its source, involving scrambling up gullies, ravines and waterfalls. As a sport, sawanobori has been practised for over 100 years, but rivers have long played a crucial role in Japan's mountainous jungle regions as the paths of least resistance for transit. Waterfalls are also sacred places in Japan, believed to be the dwellings of gods.

Toru made headlines in 2012 during a visit to the Peak District, when he was aged just 15. His ticklist included some bold and grit classics, which stunned the British climbing community:

Meshuga, E9 6c, Black Rocks, climbed in a slight drizzle and on the same day as Nocturnal Emission)
Nocturnal Emission (Direct on Parthian Shot), Burbage South E9 6c
Black Out, E9 6c, Burbage South, first ascent, solo
Simba's Pride, E8 6b, Burbage South, solo
Elm Street, E8 6c, Millstone, solo
Life Assurance E6 (onsight)

Since then, Toru has gone on to make first ascents and impressive repeats in Japan and beyond and is now primarily a boulderer, with ascents of five 8C boulder problems to his name, including Lucid Dreaming in Bishop, California.

We sent Toru a few questions about his Shomyo solo. Watch a film about his climb below, which explores the careful consideration that Toru undertook before attempting the solo, as he reflected on the gritstone solos of his youth.

I climbed Shomyo Falls two times, once last year and again at the beginning of this August. I checked out the condition of the route and noticed that it was impossible to jump across the waterline due to a large volume of water. I decided to climb on the other side of the water line, but it was still very hard due to the increase in water.

Can you explain sawanobori is, for British climbers who haven't heard of it?

It is difficult to explain what sawanobori is because of its diversity. It is kind of an opposite style of canyoning, but this explanation is not correct. The climbing style of sawanobori all depends on individual climbers. So sometimes we do aid climbing, sometimes swimming, and sometimes we climb the waterfall to go upstream.

In my case, I'm a free climber and I like to climb without heavy ropes, gear, and other stuff - so I love bouldering. Sometimes I want to climb bigger rocks and waterfalls, so in this case, I tried to do it in free solo style. There aren't any gaps between bouldering and freesoloing rock and waterfalls for me.

Is soloing a popular discipline in sawanobori?

Soloing is not famous in Japan, and it tends to be criticised. For this reason, I hesitated about doing it for a long time. But I had dreamt of doing a free solo in Japan since my first visit to the UK. Dreams come true!

Are you still rock climbing a lot?

I enjoy bouldering in Japan. I'm a PhD student and sometimes I'm too busy to climb. But fortunately, I still climb a lot. Now I'm planning to revisit Finland to complete my project, Burden of Dreams 9A.