He took a deep breath, exhaled and stepped up to the wall. Inserting his toe in the lowest notch and grabbing the highest notch on the left side, he pulled himself up. He placed his left toes in the lowest left notch and clung to the wall like a fly. His toes, inserted into the two bottom notches, supported most of his weight as he pulled himself towards the wall with the fingertips of his left hand.

Already he could feel gravity trying to pull him backwards and he pressed his fingertips against the unyielding rock to hold on. His fingers began to ache almost at once. It was going to be murderous, he thought, then pushed the thought away.

He took the chisel from between his teeth and holding on with his left hand, used his right to stab at the rock an arm’s length above his left hand. Once a sufficient notch had been cut, he repeated the process on the right side, carving a handhold parallel and about a foot away from the new left-hand notch. Then he gripped the chisel in his jaws again and inserting first his left hand and right foot into the higher notches, pulled himself up again. With both hands and feet secured to the rock face, he caught his breath for a second.

It was, he knew, the exact opposite of a normal rock climb. The professional method was to work out a path up the rock face, then climb from notch to notch maintaining a smooth ongoing rhythm, sustaining upward movement with the momentum of the climb. Ideally, the rock climber should never actually stop at any point, hanging by his fingers, where fatigue and gravity begin to take their deadly toll.

But the standard approach was impossible for the Scorpion for several reasons. The first was that he was facing an absolutely vertical surface. The sheer 90-degree face made it impossible to climb all the way up, non-stop. The second difficulty was that because of hundreds of years of erosion, water and sand particles scouring the rock, there were few if any natural crevices. The rock was steep and smooth for its entire height. Every notch would have to be hand-cut. The final and greatest difficulty was the lack of pitons. He had no way of hammering in anything to support his weight, so that he could rest and use both hands to hammer in the next upward hold.

No, this would be a slow, methodical, crab-like approach, an agonizing step-by-step process whereby he would cling by the fingers of one hand while he hammered out notches with the other. As each new pair of notches was hammered out, he would grip the chisel between his teeth like a movie pirate, then use both hands and feet to inch up to the next higher set of notches and then begin all over again.