From the Plan de l'Aiguille take trail 133/134 to the base of the Charmoz-Grepon coloir (3 hrs). Better to bivy on the Plan de l'Aiguille and get an early start vice taking the first tram up.
Once you are at the right base of the Charmoz-Grepon Coloir, look for a large curving chimney. This route starts in a crack 8 meters to the right of the chimney before converging with the chimney after one pitch. Continue up this line following the diedres and face climbing to meet the coloir then on to the top. For a more interesting finish, take the direct exit to the gap on the right of the flat-topped gendarme at 3743 meters then on to the top.
Friends, nuts, double ropes, helmet, lunch, sense of humor, etc.
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