The complete Mazeno Ridge of Nanga Parbat was undoubtedly one of the most famous unclimbed lines on the great peaks of the Karakoram/Himalaya, having been attempted many times, and by some of the world's greatest mountaineers. It is arguably the longest ridge on any of the 8,000m peaks, variously quoted as 10 to 13km. Sandy Allan and Rick Allen (U.K.), accompanied for much of the way by Cathy O'Dowd (South Africa), Lhakpa Rangdu Sherpa, Lhakpa Zarok Sherpa, and Lhakpa Nuru Sherpa (Nepal), took crossed all eight Mazeno summits to Mazeno Gap, and then, on their 10th day, climbed the southwest ridge above the gap to a bivouac at 7,200m. After an unsuccessful attempt on the unclimbed continuation of this ridge direct to the top, all but Allan and Allen made a difficult descent to the south via a variant to the Schell Route. The British pair traversed the north flank to the summit and then made a trying descent of the normal route on the north face, reaching the bottom after a traverse lasting 18 days. A full account appears here.
The Mazeno Ridge had previously been attempted by nine different parties, starting in 1979 with a large French expedition that began the route from Mazeno Pass, fixed a lot of rope, and climbed a minor summit. In 1992 Doug Scott's international team, starting from the Rupal Valley, climbed important new ground, summiting three Mazeno peaks. No one improved on this performance until 2004, when Doug Chabot and Steve Swenson traversed the ridge to Mazeno Gap, but due to illness and exhaustion were forced to descend the Schell Route to the Rupal Valley (AAJ 2005).
Previously unreported in the Journal was the 2008 traverse to Mazeno Gap by Germans Joseph Lunger and Luis Stitzinger. This pair made a long approach from Diamir base camp toward Mazeno Pass, but a little before reaching it cut up left, climbing a spur onto the main ridge well before the point reached by previous parties from the Rupal side. After seven days they reached the final (and highest) Mazeno peak (second ascent). At this point they ran out of steam and provisions, so they descended toward the gap, then escaped north via the 1978 Messner Route, which they down-climbed and rappelled in nine hours.
Lindsay Griffin, Mountain INFO