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What Is a Crux in Climbing?

LAST UPDATED: 18th July 2023

You have probably heard a few gym bros utter these works and you may now be thinking “What is a crux in climbing”?! Crux is a term that’s as intrinsic to climbing as much as words like “ropes” and “carabiners”. The significance of this four-letter word can’t be overstated.

The terminology ‘crux’ finds its home both on indoor climbing walls and amidst nature’s rocky playgrounds. Simply put, a climbing crux is the hardest and most physically demanding part of a route or boulder problem. It is the heart of a climb, marking the most demanding, arduous sequence of the line. Whether it presents itself at the route’s base, at its peak, or intermittently, the crux demands your full attention.

The crux often requires an intricate and potentially taxing sequence of moves that, despite its relatively small size, can dramatically shift a route or boulder’s grading. In the realms of mountaineering and alpine climbing, the term crux can even denote the ascent’s most perilous and dangerous sections.

Adam Ondra climbing 9c Norway
Adam Ondra working the crux on Silence 9c ©Pavel Blazek

Every climber, novice or seasoned, will have undoubtedly crossed paths with a crux, confronting its challenges and hearing tales of its trials and tribulations. Synonymous with ‘difficult,’ the crux climbing term stands as arguably the most common and most significant word that influences a climber’s experiences for better or worse.

Dive into this comprehensive guide to fully unravel the meaning, implications, and applications of the term ‘Crux’ in climbing.

Crux Climbing Definition

As mentioned, the crux of the climb is the hardest section of the route or boulder. It’s a series of moves that are significantly harder than the rest of the moves on the route. The crux can get its own bouldering grade, or be described as a boulder problem on its own.

Stefano Ghisolfi on Bibliographie 9b+
Stefano powering through the crux on Bibliographie ©mtnz.adri

To get through the crux, a climber needs to practice that move over and over again until they can get through it. You could also try the move in isolation or train specifically to get through the difficult section of the route or boulder.

While this is the proper term, let’s dive deeper – could there be a climb with no crux? Could there be a route with more than one? Can it be climbed in just one way or more?

No Crux Route

There is generally always going to be a crux in a climb. It might not be obvious to you because you’ve just flashed a V3 in the gym, but there will be a ‘hard section’ in the route, be it an awkward foot placement, a reachy jug or a dyno to the finishing hold. What you define as an easy climb might be a hard one for someone else.

There are definitely lines with no obvious crux, especially when you feel like you are crushing boulder after boulder or route after route. But, if you really sit down and think back to your last climb, can you identify a point where you though, ‘That section was reachy’, or ‘That was an awkward hand placement’. That’s your crux, even if you flashed it.

Multiple Crux(es) Route

Almost the opposite of what just described above – but yes, a climb could have more than one crux. Having multiple cruxes in a climb can make a significant impact on the whole route. It can make it a longer process to work on, or it can completely alter the grading of it. Multiple cruxes can occur on the shortest boulders or the longest sport climbs. 

You’ll find that some of the world’s hardest routes do have multiple cruxes. You can often see videos or interviews where the climber refers to several hard parts of the climb. A great example of this is Adam Ondra’s ascend of Silence, the world’s hardest route (9c).

Can a Crux Have More Than One Solution?

Almost all cruxes can be solved in various ways. We all use different beta and it’s up to each climber to find a way that will eventually solve the problem. It could be a different foothold, taking another intermediate hold, choosing another body position, or even skipping a hold if needed.

Margo Hayes Climbing Biographie 9a+
Margo Hayes on Biographie ©JanNovak

In particular, you will find that female climbers will use completely different beta than men to get through the crux. Take a look at how Margo Hayes uses a completely different beta to Chris Sharma when climbing Biographie (9a+).

Climbing Crux & Grades

Undeniably, the degree of a crux’s challenge significantly influences the grading of a route or boulder. A seemingly effortless climb can receive a harder grade solely because of an extraordinarily demanding crux in its midst.

However, it’s essential to underscore that the crux is merely one aspect factored in when assessing a route’s overall difficulty. There are instances where routes are given softer grades despite containing particularly difficult moves, especially if there are ample rest points or if the crux appears early in the route. Conversely, if the same challenging moves are situated towards the top or there aren’t any convenient resting spots beforehand, the climb could be assigned a harder grade.

Alphane V17 Boulder
Aidan Robert getting closer to the crux of Alphane ©SamPratt

As highlighted earlier, cruxes themselves can be assigned individual grades, which serve as a gauge of their difficulty and the level of challenge they present. The concept of the crux in climbing is complex and multifaceted, playing a significant role in determining the overall climbing experience.

Redpoint Crux

Are there distinct types of cruxes? Indeed there are. While the term crux in climbing broadly denotes the toughest part of a route, its character often differs when contrasting the first attempt on a route (flash or onsight) with subsequent redpoint attempts. In these instances, the crux typically manifests not as a harder set of moves or section, but as a unique element that amps up the difficulty.

Take, for instance, a redpoint crux. It might comprise a sequence of moves near the top of the route that, while not technically difficult, prove to be incredibly demanding and energy-sapping. Alternatively, it could involve moves that are tricky to memorize or discern.

As many climbers can attest, a redpoint crux can be a real thorn in your side. On the first go, these moves may not seem any more challenging than the rest, but they can quickly morph into your biggest hurdle.

On the other hand, an onsight crux or flash crux is typically influenced by the specific features of the rock. It may stem from a concealed hold or the difficulty in deciphering the sequence of moves. Interestingly, these aspects can vary significantly based on individual climbers, as their experience and interpretation play a crucial role in identifying and navigating the crux.

A Crux Expert!

The concept of the crux in climbing holds tremendous significance. It serves as an integral component of every climbing route, project, or objective. It is crucial to familiarize yourself with cruxes, train to overcome them, and not allow them to dampen your spirits.

A crux can drastically alter the nature of a climb, transforming it into a distinctive, straightforward, or challenging endeavor. We, as climbers, cherish cruxes because they propel us to strive harder, climb more robustly, and achieve greater success. The crux in climbing truly shapes our climbing experiences, pushing us towards improvement and excellence.

Watch Alex Honnold go through different sequences for the crux on Freerider!

Sam Laird

Quite likely the only idiot currently hauling a 70-meter rope and four pairs of climbing shoes around the world. Sam lives for backpacking, adventure, and of course, climbing. If he's not exploring crags and getting shut down on new projects, you can find him sharing his passion for climbing in publications such as Climbing Shoe Review,, Gear Junkie, and UK Climbing.

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