Descend the far side of the summit to a col about 100m lower then pass to the R of an obvious tower ahead, the Grande Gendarme. There is often a fixed rope up here, if not it will be the crux of the route, climbing this and then descending steeply the far side, to regain the snow crest with the imposing final summit ridge above. This is very condition dependent and can be extremely delicate if icy. Hopefully you will find it in firm snow when it is a pleasant ridge, which you follow on its R side, then L higher up. There are stanchions every 25m which can be used as belays or runners. There are two final bumps in the ridge before the summit, with its fantastic view of the many even larger 4000m peaks in all directions. The descent is the reverse of the way up. The stanchions can be used in rappel, and it is usual to also rappel the Grande Gendarme, and various parts of the E Ridge of the Wellenkuppe, before regaining your tracks on the Trift Glacier to the Rothorn Hut.