TheYosemite Decimal System (YDS) is a five-partgrading system used for rating the difficulty ofrock climbingroutes in theUnited States andCanada.[1] It was first devised by members of theSierra Club inSouthern California in the 1950s as a refinement of earlier systems from the 1930s,[2] and quickly spread throughout North America.
The class 5 portion of the class scale is primarily arock climbing classification system, while classes 1–4 are used forhiking andscrambling.[1] The current definition for each class is:[1]
The American YDS system is the dominant system in North America, and it and the French numerical system are the most dominant systems worldwide; beyond the easiest grades, they can beexactly aligned.[3][4] The exact definition of the classes is somewhat controversial,[5] and updated versions of these classifications have been proposed.[6]
Climbers use class "5" as a prefix, which is then followed by aperiod (originally adecimal point) and a number that starts at 1 and counts up with increasing difficulty (e.g. 5.4, 5.5, 5.6, etc.).[4] At 5.10, the system adds the letters "a", "b", "c", and "d" as further refinements between levels, and the scale continues upward (e.g. 5.10a, 5.10b, 5.10c, 5.10d, 5.11a, 5.11b, etc.).[1][4]
The American YDS system is an open-ended scale, with the current hardest climb being 5.15d, established bySilence in 2017. Like the French system, the numerical component of the American YDS system is focused on the hardest move on the route.[1]
In 1980, Jim Erickson introduced an additional rating fortraditional climbing routes where the level and quality of theclimbing protection are assessed.[1] The letter codes chosen were, at the time, identical to theAmerican system for rating the content of movies, except that there is no commonly recognized distinction between PG and PG13:[1][3][4]
| Code | Description |
|---|---|
| G | Good, solid protection. |
| PG | Adequate protection. Falls will not be long |
| R | Inadequate protection: potential for long fall, leader will likely suffer injuries |
| X | Protection is unavailable or so sparse that any fall is likely to result in death or serious injury. |
In 1936, theSierra Club adapted a numerical system of classification. This system, without the decimals, was initially referred to as the "Sierra Club grading system." Class 1 was a hike, and higher classes were more difficult and technical, going up to class 6, which is referred to asaid climbing.[2]
The fifth class began to be refined by climbers atTahquitz Peak inSouthern California in the 1950s.[3]Royal Robbins, Don Wilson, and Chuck Wilts came up with a decimal subdivision of the fifth class consisting of 5.0, 5.1, and so on up through 5.9. This system was implemented in the early 1950s, with new routes and ratings at Tahquitz being described inmimeographed newsletters of the Rock Climbing Section of the Angeles Chapter of theSierra Club.[citation needed] The system was originally referred to by names such as "Southern California" or "Wilts-Sierra system," but eventually came to be referred to as the Yosemite Decimal System, even though it was devised and standardized at Tahquitz, not Yosemite.[7] The first systematic presentation was in the 1956 edition of Wilts's guidebook for Tahquitz. Mark Powell is said to have exported the system to Yosemite around the same time.[8]
The standards for the fifth-class climbing grades as of 1979 were as follows:[9]
| Grade | Route | First free ascent |
|---|---|---|
| 5.0 | The trough | 1936 |
| 5.1 | White maiden's walkway | 1937 |
| 5.2 | Frightful variation of the trough | 1944 |
| 5.3 | East lark | 1950 |
| 5.4 | Angel's fright | 1936 |
| 5.5 | Ski tracks | 1947, 1957 |
| 5.6 | Sahara terror | 1942 |
| 5.7 | Fingertrip | 1946 |
| 5.8 | Mechanic's route | 1937 |
| 5.9 | Open book | 1952 |
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The original intention was that 5.9 would be the hardest possible free climb, with class 6 describing aid-climbing routes. Initially the scale was based on ten climbs at Tahquitz, and ranged from the "Trough" at 5.0, a relatively modest technical climb, to the "Open Book" at 5.9, considered at the time the most difficult unaided climb humanly possible. In later years, as gear and athletic standards in the sport became more advanced, many aid routes were "freed" (i.e., climbed without aid), and the class 6 label fell into disuse, so that 5.x could be a label for any technical rock climb, regardless of whether most people were doing it free or aided.[citation needed] By the 1960s and 70s, increased athletic standards and improved equipment meant that class 5.9 climbs from the 1950s became only of moderate difficulty for some, while new 5.9 climbs were much harder. Class 5.9 began to be subdivided as 5.9- and 5.9+. Eventually, climbers began adding classes of 5.10 and 5.11 (rendering the "Decimal" part of the Yosemite Decimal System name technically inaccurate). In the early 1970s, it was determined that the 5.11 climb was much harder than 5.10, leaving many climbs of varying difficulty bunched up at 5.10. To solve this, the scale has been further subdivided for 5.10 and above climbs with suffixes from "a" to "d".[10] As of August 2021[update], only one climb is considered to have a difficulty of 5.15d:Silence, first climbed byAdam Ondra on September 3, 2017.[11]