My first two swings of the ax glanced off the frozen waterfall. Somehow, I managed to keep my grip on the handle as the head sprang away into frigid air. I was 9 meters above a slope blanketed in snow — but nowhere deep enough to cushion any fall.

I swung again: solid contact. After a few sharp, cautious tugs, I pulled myself up to my new position and took a slow, deep breath to calm myself.

I was deep in Nagano Prefecture, midway up the third frozen waterfall of Mount Yatsugatake’s Uradoushin Gully, a well-known route among Japanese alpinists. After picking and kicking my way up icy facades up to 30 meters high, there was still one more frozen fall to climb — then an exposed traverse along the skirt of the Daidoushin Pinnacle before a descent along the top of a ridge.