A kimura is a shoulder lock used in Brazilian jiu-jitsu (BJJ), mixed martial arts, and other grappling disciplines. The attacker grips the opponent’s wrist with both hands, keeps the elbow bent at roughly 90 degrees, and rotates the arm behind the opponent’s back, forcing the shoulder joint past its natural range of motion. It’s one of the most common and effective submissions in grappling, legal at virtually all competition levels for adults.
How the Kimura Got Its Name
The technique existed long before it had this name. In judo, it’s called gyaku-ude-garami, meaning “reverse arm entanglement.” It became known as the kimura after Japanese judoka Masahiko Kimura used it to defeat Brazilian jiu-jitsu legend Hélio Gracie in 1951, winning by technical submission in the second round. Brazilian sports writers began calling the technique “Kimuriana” after Kimura returned to Brazil in 1959, and the name eventually shortened to just “kimura.” The Gracie family and the broader BJJ community adopted the name as a tribute, and it stuck across both BJJ and MMA.
How the Lock Works
The kimura attacks the shoulder by forcing excessive internal rotation. Your shoulder can typically handle about 40 to 60 degrees of internal rotation before the soft tissue structures holding the joint together start to strain. The kimura pushes well past that limit.
The attacker controls the opponent’s wrist with one hand and threads the other arm under the opponent’s elbow, gripping their own wrist to form a “figure-four” configuration. Keeping the opponent’s elbow bent at 90 degrees is critical because it turns the forearm into a lever, concentrating all the rotational force directly on the shoulder joint rather than dispersing it through the upper arm bone or elbow. The attacker then drives the opponent’s hand toward their back (and upward behind them), rotating the shoulder internally until the opponent either submits by tapping or risks injury.
The main structures under threat are the ligaments on the back of the shoulder capsule, the ring of cartilage (labrum) that cushions the joint socket, and the rotator cuff muscles that stabilize the shoulder during movement. These are the body’s primary defenses against excessive internal rotation, and the kimura is designed to overwhelm all of them simultaneously.
How It Differs From an Americana
The americana is the kimura’s mirror image, and confusing the two is common for beginners. Both use the same figure-four grip on the opponent’s arm, but they rotate the shoulder in opposite directions. The kimura forces the arm downward and behind the back (internal rotation), while the americana pushes the hand upward toward the head (external rotation). They stress different parts of the rotator cuff as a result.
An easy way to remember: if the opponent’s forearm is pointing toward their torso or hips, it’s a kimura. If the forearm is pointing toward their head, it’s an americana. Despite looking similar on the surface, the mechanics, leverage points, and setups are quite different. You can’t simply reverse one to get the other. The grips, body positioning, and angles of pressure each require their own technique.
Where You Can Use It
The kimura is one of the most versatile submissions in grappling because it can be applied from many positions. Fighters commonly set it up from closed guard (on their back with legs wrapped around the opponent), side control (pinning the opponent from the side), north-south position, and even while standing in a clinch. In MMA, it’s also used as a controlling grip to sweep opponents or force transitions, even when a full submission isn’t available.
Under competition rules set by the International Brazilian Jiu-Jitsu Federation (IBJJF), the kimura is legal for adult competitors of all belt levels in both gi and no-gi formats. Shoulder locks in general are widely permitted for grapplers over 16 years of age, from white belt through black belt, as long as they don’t involve slicing mechanics or intent to cause unnecessary harm. This makes the kimura one of the first submissions many students learn.
Injury Risk
The shoulder is one of the most mobile joints in the body, which also makes it one of the most vulnerable. Once a kimura is fully locked in, damage can happen quickly. The most common injuries include rotator cuff tears, ligament tears within the shoulder capsule, shoulder dislocations, and in severe cases, fractures of the upper arm bone (humerus). Masahiko Kimura himself reportedly broke Hélio Gracie’s arm with the technique in their 1951 match when Gracie refused to tap.
In training, the standard practice is to apply the lock slowly, giving your partner time to recognize the submission and tap before any damage occurs. In competition, fighters who wait too long to tap risk significant injury that can require surgery and months of rehabilitation. The speed at which the kimura transitions from uncomfortable pressure to structural damage is one of the reasons it remains so respected and feared across grappling sports.