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In the U.S., rock climbing routes are rated on the Yosemite Decimal System. All technical rock climbs (requiring the use of ropes, protection hardware and related techniques) are rated class 5, with the difficulty rating tacked on behind the decimal point. The open-ended scale currently ranges from 5.0 (easiest) to 5.15. More often than not, routes are rated according to the most difficult move.
Scott Willoughby, The Denver Post
