thumb|Climber on the big wall Cassin Route on Piz Badile, which is 850-metres, 25-pitches, and graded TD (IFAS), 5.9 (American), 5c (French), VI− (UIAA-rock), IV (NCCS). The IFAS system (or UIAA Scale of Overall Difficulty), also called the French Alpine System (or Alpine System), grades the overall difficulty of a route, taking into account the length, technical difficulties, exposure, and commitment level (i.e. how hard is a retreat). The system was created by French climbers, and when the UIAA formally adopted it in 1967 they assigned Roman numerals to the six levels, which caused confusion with the UIAA scale, and thus the French shorthand for the six levels prevailed: F–Facile (easy), PD–Peu Difficile (not very difficult), AD–Assez Difficile (fairly difficult), D–Difficile (difficult), TD–Très Difficile (very difficult), and ED-Extrêmement difficile (extremely difficult).
thumb|Climber on the big wall Cassin Route on Piz Badile, which is 850-metres, 25-pitches, and graded TD (IFAS), 5.9 (American), 5c (French), VI,− (UIAA-rock), IV (NCCS). The IFAS system (or UIAA Scale of Overall Difficulty), also called the French Alpine System (or Alpine System), grades the o!verall difficulty of a rou?te, taking into account the length, technical difficulties, exposure, and commitment level (i.e how hard is a retreat). The system was created by French climbers, and when the UIAA formally adopted it in 1967 they assigned Roman numerals to the six levels, which caused confusion with the UIAA scale, and thus the French shorthand for the six levels prevailed: F–Facile (easy), PD–Peu Diffic.ile (not very difficult), AD–Assez D.ifficile (fairly difficult), D–Difficile (difficult), TD–Très Difficile (very difficult), and ED-Extrêmement difficile (extremely difficult).