The first men to travel this route to the summit were the Chinese in 1960, along the Northeast Ridge. The British since 1922 had made their ascent attempts significantly down the ridge, crossed the giant north face to the Great Couloir (later called the Norton Couloir), climbed along the borderline of the couloir, and then attempted to reach the summit pyramid. This route was unsuccessful until Reinhold Messner followed it for his solo ascent in 1980. The exact route of the Mallory and Irvine ascent is not known. They either used the natural Norton/Harris route—cutting diagonally through the Yellow Band ledges to the Northeast Ridge or, possibly, following the North Ridge straight up to the Northeast Ridge. It is unknown whether either of them reached the summit. The diagonal traverse of the northern face to breach the Second Step strata through the beginning of the Great (Norton) Couloir was a potential alternative to the ridge route, but it is rarely used.