Editing Grade (climbing) (section)

==History==
[[File:Echelle des six degrés de difficulté en escalade rocheuse.jpg|thumb|The six levels (Grade I–VI) of the "Welzenbach scale", from 1926]]
In 1894, the Austrian mountaineer {{ill|Fritz Benesch|de|Fritz Benesch (Alpinist)}} introduced the first known climbing grading system, which he introduced to rock climbing. The "Benesch scale" had seven levels of difficulty, with level VII the easiest and level I the hardest; as more difficult climbs were made, the grades of level 0 and level 00 were added.<ref>{{cite book | title=Continental Divide: A History of American Mountaineering | first= Maurice |last=Isserman | author-link=Maurice Isserman | date=2017 | publisher=[[W. W. Norton & Company]] | edition=reprint | isbn=978-0393353761}}</ref>

In 1923, German mountaineer {{ill|Willo Welzenbach|de}} compressed the scale and reversed the order so level 00 became level IV–V, and it became popular in the Alps. In 1967, the "Welzenbach scale" formally became the "UIAA scale" for rock climbing (or "UIAA Scale of Difficulty") with Roman numerals I–VI, and a "+" and "−" to refine each level.  The UIAA also incorporated proposals made in 1943 by {{ill|Lucien Devies|fr}} and the {{ill|Groupe de Haute Montagne|fr|Groupe de haute montagne}} on a broader "Scale of Global Assessment"  for alpine climbing (the French Alpine System), and created the "UIAA Scale of Overall Difficulty" by assigning Roman numerals I–VI to the six adjectival levels (e.g. F, PD, AD, D, TD, and ED) of the French system. The UIAA also incorporated a "Scale of Difficulty in Aided Climbing" for [[aid climbing|aid routes]] with the levels: A1, A2, A3, A4, and (later) A5. In 1978, the UIAA added the VII (seventh grade) to its "UIAA scale", implying that the scale was open-ended, a concept formally adopted in 1985.<ref name=CAI/>

By the 1980s, French guides had customized the "UIAA scale" beyond V+ with the letters "a", "b", and c" (e.g. V+, VIa, VIb, etc.). At the end of the 1980s, French [[climbing guidebook]] author {{ill|Francois Labande|fr}} published the "French numerical scale", which replaced the UIAA Roman numerals with Arabic numerals, and where French 6a equaled UIAA VI+. The two scales were summarised as "Plaisir Grades" and aligned in a UIAA table where French grades 1–6a aligned with "UIAA scale" grades I–VI+; beyond that level, the two systems diverged and for example, French 7a+ equates to UIAA grade VIII and French 9a equates to UIAA grade XI.<ref name=CAI/>

In America, a version of the Welzenbach Scale was introduced for rock climbing in 1937 by the [[Sierra Club]], which in the 1950s was further adapted into the Yosemite Decimal System that added a decimal place to the class 5 grade (e.g. 5.2, 5.3, 5.4, etc.), and which by the 1960s was again amended to introduce the letters  "a", "b", "c", and "d" after 5.9 to further refine the levels (e.g. 5.9, 5.10a, 5.10b, 5.10c, etc.).<ref name=CAI/>

While individual countries developed their own rock climbing grading systems, the American system, French system, and latterly the "UIAA scale" became popular internationally (with the American and French dominating sport climbing). The UIAA "Scale of Overall Assessment" dropped its six Roman numbers in favor of the six adjectival grades of the French Alpine System (to avoid confusion with the "UIAA scale") and dominated alpine climbing grading, while the UIAA "Scale of Difficulty in Aided Climbing" – amended and expanded in Yosemite in the 1990s as "new-wave" grades – dominated aid grading.<ref name=CAI>{{cite web <!-- Deny Citation Bot--> | first1=G |last1=Mandelli |first2=A |last2=Angriman | date=2016 | title=Scales of Difficulty in Climbing | publisher=Central School of Mountaineering, [[Club Alpino Italiano]], Italy | url=https://www.semanticscholar.org/paper/SCALES-OF-DIFFICULTY-IN-CLIMBING-Mandelli-Angriman/71aa9bf83711bd677aef61b6feec20bbcfc08aaf#related-papers | accessdate=4 May 2023}}</ref>