Yosemite Decimal System

The Yosemite Decimal System (YDS) is a three-part system used for rating the difficulty of walks, hikes, and climbs. It is primarily used by mountaineers in the United States and Canada. The Class 5 portion of the Class scale is primarily a rock climbing classification system, while the Classes 1-3 are used mainly in hiking and trail running. Originally the system was a single-part classification system. In recent years, Grade and Protection categories were added to the system. The new categories do not apply to every climb and usage varies widely. The grades are subjective, reflecting the first ascenscionist's opinion of the climb's difficulty.

While primarily considered a free climbing system, an aid climbing designation is sometimes appended. For example, The North America Wall on El Capitan would be classed "VI, 5.8, A5" using this mixed system.

YDS class

The system was initially developed as the Sierra Club grading system in the 1930s to classify hikes and climbs in the Sierra Nevada. Previously, these were described relative to others. For example, Z is harder than X but easier than Y. This primitive system was difficult to learn for those who did not yet have experience of X or Y. The club adapted a numerical system of classification that was easy to learn and which seemed practical in its application.

Guidebooks often append some number of stars to the YDS rating, to indicate a climb's overall "quality" (how "fun" or "worthwhile" the climb is). This "star ranking" is unrelated to the YDS system, and varies from guidebook to guidebook.

The system now divides all hikes and climbs into five classes: The exact definition of the classes is somewhat controversial, and updated versions of these classifications have been proposed.

• Class 1: Walking with a low chance of injury, hiking boots a good idea.
• Class 2: Simple scrambling, with the possibility of occasional use of the hands. Little potential danger is encountered. Hiking Boots highly recommended.
• Class 3: Scrambling with increased exposure. Handholds are necessary. A rope should be available for learning climbers, or if you just choose to use one that day, but is usually not required. Falls could easily be fatal.
• Class 4: Simple climbing, with exposure. A rope is often used. Natural protection can be easily found. Falls may well be fatal.
• Class 5: Is considered technical roped free (without hanging on the rope, pulling on, or stepping on anchors) climbing; belaying, and other protection hardware is used for safety. Un-roped falls can result in severe injury or death.
  • Class 5.0 to 5.15c is used to define progressively more difficult free moves.
• Class 6: Is considered Aid (often broken into A.0 to A.5) climbing. Equipment (Etriers, aiders, or stirrups are often used to stand in, and the equipment is used for hand holds) is used for more than just safety.

Information about the difficulty of a summit block is sometimes added. For example, a rating of 3s4 means that most of the climb is class 3 but the summit block is class 4.

The original intention was that the classes would be subdivided decimally, so that a class 4.5 route would be a climb halfway between 4 and 5. Class 5 was subdivided in the 1950s. Initially it was based on ten climbs of Tahquitz Rock in Idyllwild, California, 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. This system was developed by members of the Rock Climbing Section of the Angeles Chapter of the Sierra Club.

Increased standards and improved equipment meant that class 5.9 climbs in the 1960s became only of moderate difficulty for some. Rather than reclassify all climbs each time standards improved, additional classes were added. It soon became apparent that an open-ended system was needed and further classes of 5.11, 5.12, etc. were added. It was later 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 above the 5.9 mark with suffixes from "a" to "d". As of 2013, two climbs are considered to have a difficulty of 5.15c: Change, first climbed by Adam Ondra in October, 2012 and La Dura Dura, first climbed by Adam Ondra in February, 2013 and repeated by Chris Sharma in March, 2013.

The original Sierra Club grading system also had a Class 6, for artificial, or aid climbing. This sort of climbing uses ropes and other equipment where progress is made by climbing directly on equipment placed in or on the rock and not the rock itself. Class 6 is no longer widely used. Today aid climbing uses a separate scale from A0 through A5.

Classification of climbs between indoor gym, sport and traditional climbing can also vary quite a bit depending on location and history.

A formula that combines average speed, class of climb, distance and elevation gain for use in planning has yet to be published.

YDS grade

The YDS grade system involves an optional Roman numeral grade that indicates the length and seriousness of the route. The grades are:

• Grade I: One to two hours of climbing.
• Grade II: Less than half a day.
• Grade III: Half a day climb.
• Grade IV: Full day climb.
• Grade V: Two day climb.
• Grade VI: Multi-day climb.
• Grade VII: A climb lasting a week or longer.

The Grade is more relevant to mountaineering and big wall climbing, and often not stated when talking about short rock climbs.

YDS protection rating

An optional protection rating indicates the spacing and quality of the protection available for a well-equipped and skilled leader. The letter codes chosen were, at the time, identical to the American system for rating the content of movies:

• G: Good, solid protection.
• PG: Pretty good, few sections of poor or non-existent placements.
• PG13: OK protection, falls may be long but will probably not cause serious injury.
• R: Runout, some protection placements may be very far apart (possibility of broken bones, even when properly protected).
• X: No protection, extremely dangerous (possibility of death even when properly protected).

The G and PG ratings are often left out as they are typical of normal, everyday climbing. R and X climbs are usually noted as a caution to the unwary leader. Application of protection ratings varies widely from area to area and from guidebook to guidebook.

Other systems

There are other systems used throughout the world. They are covered in the article about Grade (climbing).

See also

• Aid climbing
• Ice climbing
• Grade (climbing)