Jannu. In September and October of 1957 Guido Magnone, Jean Bouvier, and Pierre Leroux made a quick reconnaissance of three sides of Jannu (25,294 feet), following Yalung, Yamatari, and Jannu glaciers to their sources. They do not report any obvious route up this peak, which promises to be a difficult problem for the French expedition planned for the spring of 1958.