Traverse along the ridge to the west of the pisteurs hut at the top of the Aiguille Percée chair, as for the Sachette variant of the Vallon de la Sache. Drop down to a col, before taking your skis off and climbing the shoulder of the peak in front of you, until you can climb no further. At this point, put your skis back on and traverse across the north facing slope above the Sachette valley, aiming for a narrow, steep couloir. Skis off again to climb this couloir, which can be a very difficult climb in deep snow and has tricky rocky parts to negotiate. Once past the couloir, there's a snowfield to climb through to the jagged summit. The couloir has a few different entries of varying technicality, some may be protected by a cornice depending on conditions.