Crack Climbing Technical Guide: Core Concepts and Terminology

Introduction

Crack climbing is a unique and technically demanding branch of rock climbing. Its core lies in understanding the geometric form (topology) of cracks and mastering corresponding body movements (jamming, opposition, etc.).

This article aims to systematically introduce the types, characteristics, related terminology, and common technical movements of cracks, providing climbers with a clear cognitive framework.

I. Core Crack Topology

The geometric shape of a crack is its most fundamental characteristic, directly influencing climbing strategy:

1. Corner / Dihedral / Open Book:

• Definition: An acute or right-angle area formed by the intersection of two rock faces. Imagine an open book.

• Variants:
  • Acute Dihedral: Angle less than 90 degrees.
  • Obtuse Dihedral: Angle greater than 90 degrees.
  • Offset / Shallow Corner: A very shallow dihedral, typically protruding only a few inches or less from the main wall face. Often formed by one side of a parallel crack being offset.
  • Changing Corner: A corner formed where the crack direction changes (e.g., turning from left to right).
  • Left-Facing Corner: A corner where the side wall faces left relative to the overall cliff.
  • Left-Hand Corner: A corner where the natural climbing motion involves raising the left hand high (Note: Defined by climbing motion, different from “Left-Facing Corner” which defines the angle).

2. Splitter:

• Definition: A crack with roughly parallel sides cutting through a single plane. Typically refers to vertical cracks.
• Key Point: “Splitter” primarily describes the geometric shape, not necessarily the crack quality.

3. Leaning Crack / Leaner:

• Definition: A crack that tilts overall to the left or right on the rock face (not vertical). Often formed by offset parallel cracks.
• Impact: Forces climbers to use specific directional opposition (e.g., sidepulls to the left or right).

4. Angled to Face:

• Definition: A crack splitting the rock wall at a non-90-degree angle.
• Extreme Example: Slab Crack.

5. Flare:

• Definition: A crack where the opening width is not constant.
• Standard Flare: Wider at the opening, narrower inside.
• Inward Flare: Narrower at the opening, wider inside.
• Impact: Significantly increases jamming difficulty and unreliability.

6. Rounded Edges:

• Definition: Crack edges weathered or eroded into a rounded shape, rather than sharp corners.
• Impact: Reduces the reliability and friction of jams.

II. Crack Sizing Classification

Crack width determines usable jamming body parts and techniques:

1.Tips Crack: Only fingertips can fit.

2.Thin Fingers: Can fit up to the first finger joint.

3.Finger Crack: Can fit fingers up to the second joint.

4.Tight Hands: Width barely accommodates the first three knuckles (palm cannot fully insert).

5.Hand Crack: Perfectly accommodates the entire hand (natural size).

6.Thin Hands / Narrow Hands: Width between finger and hand crack, difficult to fully insert the hand (synonymous with Tight Hands in some contexts).

7.Fist Crack: Perfectly accommodates a fist (natural size).

8.Off-width (OW): Width between fist crack and body width (approx. 0.75 – 1.5 body widths), precluding reliable hand or fist jams; a technical crux. Often described as “Fat (Definition 2)”.

9.Rattley / Fat (Definition 1): Slightly wider than comfortable hand/fist jams, resulting in unstable jams (prone to rattling).

10.Chimney: Width sufficient to accommodate the entire body (typically >1.5 body widths).

11.Box / Elevator Shaft: Width less than body width but greater than fist crack, with shallow depth (typically <0.6 meters deep), requiring specific body techniques.

• Box: Typically refers to shallower features of this type.
• Elevator Shaft: Typically refers to a deeper, more enclosed shallow chimney formed by two opposing dihedrals.

III. Crack Features & Challenges

Irregularities in the crack walls present specific challenges or opportunities:

1.Crack Features: Refers to any variation on otherwise parallel or flat crack walls:

• Constriction: The crack narrows.
• Bulge: A localized outward protrusion on the crack wall.
• Grain: Small texture on the rock surface.
• Nubbin: A small protruding crystal or pebble on the rock surface.
• Flare: As previously defined.
• Rounded Edges: As previously defined.
• Pod: A locally widened section within a crack (common in desert sandstone).

• Dogleg: A significant directional bend in the crack (angle typically <45 degrees).

2. Impact: These features can complicate climbing (e.g., causing unreliable jams – Manky Jam) but can also be skillfully exploited by experienced climbers (e.g., Working a Jam – utilizing specific positions for multi-directional jamming/opposition).

3. Bias: A general term for any crack feature (e.g., corner, offset, leaning crack, slab crack, one-sided rounded edge) that forces the body to lean left or right to apply opposition or maintain balance. Often leads to “barn dooring”.

4. Transition Size: Width slightly wider or narrower than a natural size (e.g., finger, hand, fist crack), requiring climbers to use jams or techniques outside their comfortable range.

5. Off-Size: Specifically refers to cracks between natural sizes, typically meaning off-width or thin hands, requiring specialized techniques.

6.Barn Door: (Verb) Describes the tendency of the body to swing sideways like a door due to loss of lateral support (e.g., on biased features). Often countered with flagging (Flag).

7. Nonlinear: Refers to the disproportionate relationship between input (effort/skill) and output (movement effect/stability). For example, in flares or on rounded edges, a small movement error can have severe consequences (consequences amplified), while finding a precise jam point offers great stability (benefits amplified).

IV. Essential Climbing Techniques & Actions

1. Jam: The core technique of wedging hands, feet, or body parts into the crack to generate friction and support. The goal is to achieve a natural size jam.

• Overjam: Using more force than necessary (e.g., over-bending fingers/palm) to create a jam, leading to fatigue.
• Manky Jam: An unstable, unreliable jam in flares, rounded edges, or shallow cracks.

2. Lieback: Facing sideways to the crack, pulling inwards on the crack edge (or sidewall edge) with hands, while pushing outwards with feet against the opposite rock wall (or inside the crack), creating opposition.

3. Lay-away: An incomplete lieback motion with insufficient opposition.

4. Undercling: Gripping a downward-facing hold and pulling upwards or outwards with arms, while pushing downwards or inwards with feet to create opposition. Similar to an upside-down lieback.

5. Gaston: Gripping a sidepull hold (often a crack edge or independent hold) in front of the body, pushing elbows outwards to the sides (like opening sliding doors) to counteract the tendency to fall into the crack.

6. Flag: Extending one leg and pressing it against the rock wall (without stepping on a hold) to maintain body balance, especially when countering barn dooring.

7. Body English: A general term for the collection of core and whole-body movements used to aid climbing that are difficult to describe standardly (e.g., arching back, body squeezes, hip thrusts, smearing, wriggling), crucial in off-widths and chimneys.

8. Thrutch: Describes a struggling, inelegant climbing state involving ungainly limb movements and a lack of fixed technique, common in off-widths and other difficult terrain.

9. Yard / Yarding: Typically refers to a powerful pull relying mainly on brute force rather than technique.

10. Pendulum: A swinging motion of the body like a pendulum, used to bypass obstacles or reach distant holds.

11. Engram: A body movement or balanced position achieved in an unconscious state through prolonged, repetitive practice (muscle memory).

V. Rope Systems Terminology

1. Double Rope System: Lead climbing using two ropes. Typically, ropes are clipped alternately into protection points, or one rope clips left-side points and the other clips right-side points (not necessarily clipping both ropes into every point).

2. Twin Rope System: Lead climbing using two ropes where both ropes must be clipped into every protection point simultaneously.

3. Haul Line: A thicker rope (typically 9-11mm diameter) carried and pulled up by the leader, used for hauling packs, etc.

4. Zip Line / Tag Line: A very thin rope (typically 4-6mm diameter) carried and pulled up by the leader, used for hauling small amounts of extra gear.

VI. Body Metrics Terminology

• Ape Index: Ratio of armspan (fingertip to fingertip) to height.

VII. Specific Wall Features Terminology

1. Crack Wall: The surface within a corner/dihedral where the crack itself runs. Contrasts with the Side Wall.

2. Wall of Dihedral / Dihedral Face: In a dihedral feature, the face that is perpendicular to the overall cliff line. Contrasts with the Main Wall (the face parallel to the cliff line).

3. Side Wall: In a corner/dihedral feature, the other rock face that intersects with the Crack Wall to form the corner angle.