There are many knots that can be useful in the mountains. But it's better to know six good ones than thirty, but bad. We asked our ambassador, an experienced climber, instructor of the Tuyuk-Su alpine camp, Kirill Belotserkovsky, to tell us which knots for mountaineering should be learned in the first place, why they are needed and how to tie them. We recommend taking a piece of turnip or rope to try right away.

Basic rules for knitting climbing knots
It is necessary to learn to knit knots and practice in advance in order to work confidently in the mountains and not ask the partner on the other end of the rope what to do. Here are simple rules that will help you master the art of knitting knots.
Observe the correct pattern of the node. This will help you quickly identify the error if you have tied the knot incorrectly.
Straighten and tighten the knot. If there are overlaps in the node, and there are lumens in the body of the node, under load it will tighten incorrectly. Such a knot will be very difficult to untie.
Leave the free end of the desired length. For most knots, it should be at least 10 rope diameters. But there are exceptions: for the node "Oak" - at least 30 centimeters.
If in doubt whether the knot is tied correctly, do not apply it. Tie one that you know well.
The knots you use should be simple and easy to remember. On the route, you need to think about the route itself, and not remember the tricky knot.

Knot"Eight" in mountaineering
The "Eight" knot is one of the most popular, simple and reliable knots in mountaineering. This is the first  that beginners are taught. It is difficult to make a mistake in it: the drawing is recognizable and understandable.
The "eight" has several options that can be used for different purposes. With this knot in mountaineering, the rope is tied to the harness, the ropes are tied together and auxiliary loops are made.
 
How to properly knit the knot "Eight":
All strands of the knot should go in parallel, without overlaps, and not pinch each other.
Tighten each strand separately, otherwise under load the "eight" will tighten incorrectly or even untie.
Leave a small eye of the "eight". If the knot is used with a carabiner, the loop should be such that the carabiner fits freely, if without a carabiner - along the length of the safety ring on the harness. Too large an ear creates a mess on the belt, besides it is an irrational expenditure of the rope.
Leave the free end of at least 10 rope diameters. If the end is smaller, then there is a possibility that on a poorly tightened knot it will crawl into the body of the node, and the knot itself will untie, if longer it will interfere when working with the rope.
Importantly

The control knot on the "eight" is not necessary to knit. The knot does not untied under load if it is well and correctly tightened. But if you have just started using a new slippery and hard rope and do not know how the knots on it behave, knit a control one.
Grapevine Mountaineering Junction
"Grapevine" has a characteristic pattern and is easy to control. With this knot in mountaineering, a turnip is tied for a station or ropes are connected when one long string is needed. You can tie a rope or ropes of the same or different diameters. "Grapevine" reduces the strength of the rope less than other knots. The only disadvantage of the node is that it is greatly tightened under load.
How to properly knit a knot "Grapevine":
It is necessary to knit the "crosses" of the knot in different directions, then the two halves rest on each other, and the pattern of the knot turns out to be correct - similar to XX.

"Oak" knot in mountaineering
A simple knot in mountaineering, quickly knitted and untied, but its main advantage is that the knot easily bypasses all obstacles. Therefore, it is used when you need to tie two ropes to go down, and then pull the rope. The smaller the node, the more likely it is that it won't get stuck. You can tie ropes and "grapevine", but "oak" is more compact and knotted faster.
Compared to other knots, the "oak" eats up a greater percentage of the strength of the rope, but when you go down, there are no loads on it, except for the weight of the climber, so the margin of safety is more than enough.
To appreciate the ease of tying knots, try tying "grapevine" and "oak" with a stopwatch. It took me 33 seconds for the Grapevine and 14 seconds for the Oak. I spent 48 seconds in thick mittens on Grapevine and 13 seconds on Oak Mittens.
How to knit the "Oak" knot correctly:
Leave the loose ends long - from 30 to 60 centimeters, because a poorly tightened knot can "go".
If you doubt the reliability of the knot, tie another "oak" at the ends coming out of the knot.
UIAA node in mountaineering
The UIAA node, aka the fire station or the Munter node. UIAA creates a strong friction of the rope on the carbine, it is easy to control, so you can insure the leader, the second participant, go down yourself if there is no basket or gris-gris, or lower the victim. The knot works both ways: when you pull the working end of the rope, it will turn into the one you need.
When descending the victim with an escort or on thin ropes, a double UIAA or super UIAA with an additional carbine is knitted. They create more friction than a single one, so it is easier to control the speed of descent, you can lower a heavy load or work with a thin rope.
The UIAA knot twists the rope, be prepared for the fact that there will be "lambs" on it.
How to properly knit a UIAA knot:
To work with the UIAA unit, it is better to use pear-shaped coupling carabiners (HMS).
Make sure that the movable part of the rope is on the opposite side of the clutch of the carbine and does not spin it.
If you need a control knot, knit it as close to the UIAA as possible.

Prusik's knot in mountaineering
Prusik's node refers to the grasping nodes. The principle of operation of such nodes is that in the unloaded state they can be freely moved along the rope, and under load due to the large friction force, they "grasp" the rope. The Prusik knot is the most popular and most used node of this type. It is needed for safety when descending, climbing a rope or for rescue operations. It is knitted on the main rope with a separate piece of turnip. There are other grasping knots that are a little more comfortable in a given situation, but this one works well enough in any.
How to properly knit a Prusik knot:
Use a turnip with a diameter of 6 or 7 millimeters, it holds well on the main rope with a thickness of 9-11 millimeters.
Make three turns around the main rope, if its diameter is from 9 to 11 millimeters. In general, the larger the diameter of the rope, the less revolutions are required. The thicker the turnbuckle, the more revolutions.
Straighten out all the overlaps so that the knot "grabs" effectively.

Stirrup Knot in Mountaineering
"Stirrup" is used wherever you need to rigidly fix the rope. Self-insurance is made of it, railings or strands of the station are hung on it. The main advantage of the "stirrups" over the loops of other nodes is that it is easy to untie after the load. It is enough to pull out the carbine, and nothing will remain of the knot.
How to properly knit the knot "Stirrups":
Tighten each strand properly so that they clamp the carabiner tightly.
To use it for self-insurance, learn how to quickly knit "stirrups" on a carbine with one hand. At first it will be unusual, then it will become unclear how and why to knit differently.

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