Years ago, one of my young students came to judo practice and excitedly told me, “This judo stuff works!” It was this “judo stuff” that enabled him to throw a neighborhood bully and defend himself. That young student grew up to become a successful judo athlete who continued to prove that “this judo stuff works” against a variety of opponents during his long career. The point of the story is this: judo really does work. It works because it’s based on sound mechanical principles as well as on the forces of gravity and how the human body moves based on the forces of gravity. Gravity works and gravity always wins.

Every technique, action, or movement used in judo is based on a core principle: the principle of kuzushi. Kuzushi translates to “breaking” and means controlling an opponent’s body and movement, breaking his posture and balance. Kuzushi is the initial action that makes it possible to take further control of an opponent and successfully increase, control, and apply the force necessary to throw an opponent. Every movement in judo is based on kuzushi. Kuzushi is controlling the initiation and direction of force; how you make force happen and where you send or guide that force in order to successfully apply a technique. It’s the breaking of an opponent’s posture and balance and then taking control of the situation. The principle of kuzushi works both in throwing techniques as well as ground fighting techniques.

Types of Kuzushi

There are six distinct types of movement that create kuzushi, all based on natural body movements. These are the first movements in the initial action of a technique that enable further application of the technique. Every judo technique uses one (or more) of these types of movement. Knowing these elements can be helpful to you when you want to work out some technical answers as to why, how, and when a specific technique works. For the sake of clarity, the term tori (taker or thrower) will be used and uke (receiver of the technique) will be used to explain them.

Explosive and Continuous Force: This is one application of kuzushi where an immediate, sudden, and explosive concerted force flows directly in an accelerated action to break and control uke’s balance. After an explosive action that starts an application of force, tori continues to apply that force in a specific direction. Doing this increases the force being applied. Just like a boulder rolling down a hill and increasing its speed as it rolls, a defender’s body can be controlled by an initial strong and sudden application of force that can be made stronger by continuous control by the attacker. This form of kuzushi is simple and effective. This application of kuzushi is best illustrated by the Kodokan principle of “happo no kuzushi” where there are eight directions a human body can be moved in order to break and control balance and then apply a technique as momentum is accelerated.

Yielding and Adapting to an Opponent: Pull when an opponent pushes you and push when he pulls you. This is one of the most well-known applications of kuzushi, but it’s important to remember that the first part of it (yielding) requires the second part of it (applying your own force) for it to work. This type of kuzushi works well when both the attacker and defender are moving in a straight line. A judoka need only take one step to initiate this action for it to work. In this type of kuzushi, tori will react to uke’s movement, and it is the opposite of the next type of kuzushi I describe.

Using a Reaction: This is a situation where a tori will initiate a movement, forcing his opponent to react. When the opponent reacts, tori will adapt to the situation and yield to the opponent’s initial force and then move in such a way that he will apply his own force, creating more momentum. By doing this, tori is multiplying force and directing it where he wants it to go. This increased momentum breaks and controls an opponent’s balance and enables him to be thrown. In other words, tori does something to make uke react, and when he does, tori takes advantage of the situation. This is called “hando no kuzushi” in Kodokan judo, meaning “break balance by creating a reaction.”

Taisabaki-Circular Movement: One of the most popular and effective movement patterns used in judo is taisabaki (moving an opponent in a circular pattern). Taisabaki works because tori moves uke in a circular direction and stands in the middle of the circle. Exactly in the same way the hub of a wheel works, tori acts as the hub. Tori moves in a small circle with uke moving in a wider circle around him. The judoka (tori) moving in the smaller circle has more balanced movement because he is controlling the judoka (uke) moving in a wider circle. A good example is for a judoka to use the taisabaki movement pattern to pull his opponent closer to him and load the opponent up and onto his hip, then apply a throwing technique such as seoi nage (back carry throw) or tai otoshi (body drop).

Upper Body/Lower Body Movement: In this application of kuzushi, the upper half of a judoka’s body moves at a different speed and in a different direction than the lower half of his body. One of the most common ways that this application of kuzushi is used in when using foot sweeps, such as okuri ashi barai (send after foot sweep). Tori initiates the action by both judo athletes gripping each other and facing each other with tori moving uke in a lateral (side) direction (with the attacker moving to his right and with the defender moving to his left). As both judo athletes move, momentum increases and the attacker uses his left foot to sweep the defender’s right ankle. The defender’s feet are swept out from under him quickly. When this happens, uke’s feet are moving faster than his upper body is moving; his feet are moving in one direction (to his left side) and his upper body is moving in the opposite direction (to his right side) as his body moves through the air. The uke’s body is literally upended and he is thrown off the mat and through the air. What takes place is the velocity of the defender’s lower body moves faster than the velocity of his upper body in the opposite direction.

Sacrifice/Body Weight: These are the throwing techniques where the attacker falls to the mat in order to throw his opponent. In Kodokan judo terminology, this type of a technique is called a sutemi waza, which translates to “sacrifice technique.” The attacker uses the weight of his body to start the process of kuzushi and “sacrifices” his own body’s balance to break and control his opponent’s balance. In practical terms, tori will move his body under the center of gravity of uke, using the weight of his own body to break uke’s balance, which enables tori to continue to use his body weight to form or develop the technique that will throw the opponent. Tomoe nage (circle throw) is a classic example of using this type of kuzushi. Tori and uke are facing each other with both gripping each other. Tori steps in deeply with his base leg (his right leg) as he swings his hips between uke’s legs and deeply under the defender’s center of gravity. As he does this, tori places his right foot at uke’s waistline to provide a fulcrum that uke will go over. At this point, tori’s body is formed in a round position and the weight of his body swinging under uke’s body creates the necessary momentum to throw uke forward and over the head and rounded body of the tori.

The above is an excerpt from Winning Judo: Realistic and Practical Skills for Competitive Judo by Steve Scott, Publication Date June 2024, YMAA Publication Center, ISBN 9781594399848.