Defendu: The Pioneering Self-Defense System That Revolutionized Self Defense Training
- William DeMuth
- Jan 14, 2025
- 4 min read
Updated: Dec 26, 2025
In over a hundred years of self-defense training, few systems have left as indelible a mark as Defendu. Developed in the early 20th century by British officer William E. Fairbairn, Defendu is a pragmatic, no-nonsense approach to personal defense that prioritizes efficiency and effectiveness over complexity. Its influence extends beyond individual self-defense into military and law enforcement training, shaping modern close-quarters combat tactics worldwide.
Origins of Defendu
The genesis of Defendu can be traced back to Fairbairn's tenure with the Shanghai Municipal Police (SMP) in the 1920s and 1930s. Tasked with maintaining order in one of the world's most dangerous cities, Fairbairn encountered a wide array of violent confrontations. He recognized the inadequacy of traditional martial arts and combat techniques in real-world, high-stress situations.
Drawing on his extensive experience and study of various martial arts—including judo, boxing, and savate—Fairbairn devised a system that emphasized simplicity and adaptability. The result was Defendu, a method that could be learned quickly and applied effectively under pressure.
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Core Principles of Defendu
At its heart, Defendu is a combat system designed for survival. Its principles include:
Simplicity: Techniques are straightforward and easy to execute, making them accessible to individuals with limited training time.
Efficiency: Every movement is designed to neutralize a threat swiftly, often by targeting vulnerable areas of the body such as the eyes, throat, or groin.
Practicality: Defendu focuses on real-world scenarios, equipping practitioners to handle unexpected attacks, multiple assailants, and armed adversaries.
Aggression: The system emphasizes controlled aggression to overwhelm opponents and gain the upper hand in a confrontation.
The Evolution of Defendu
Fairbairn co-authored "Defendu: Scientific Self-Defence" in 1926 with his colleague Eric A. Sykes. The book detailed their techniques and philosophy, setting the foundation for future developments.
During World War II, Fairbairn and Sykes further refined Defendu for military use, incorporating additional elements tailored to close-quarters combat. This version became the foundation of the Silent Killing Course, taught to Allied commandos and special forces. The Fairbairn-Sykes fighting knife, a dagger designed for close combat, is another enduring legacy of their collaboration.
Second World War
During the Second World War, Defendu became a cornerstone of close-combat training for Allied forces, thanks to its simplicity and brutal efficiency. William E. Fairbairn and Eric A. Sykes, both former members of the Shanghai Municipal Police and experienced in real-world combat scenarios, adapted the system to meet the needs of military personnel.
They refined Defendu into a streamlined method that prioritized quick, decisive actions to neutralize an opponent, often in high-stakes, life-or-death situations. This evolved version of Defendu was taught to elite units such as British Commandos, the Special Operations Executive (SOE), and the American Office of Strategic Services (OSS) precursor to the todays CIA.
Training emphasized disabling techniques, including strikes to vital areas, escapes from holds, and the effective use of knives and improvised weapons. The system's practicality and adaptability made it invaluable for soldiers and covert operatives operating behind enemy lines, solidifying its legacy as one of the most influential hand-to-hand combat systems of the era.
Modern Influence of Defendu
Defendu's impact is evident in many contemporary martial arts and self-defense systems. Military organizations, law enforcement agencies, and security professionals continue to draw from its principles. Systems like Krav Maga and modern combatives share its emphasis on simplicity, efficiency, and adaptability.
Moreover, Defendu's philosophy resonates with civilian self-defense practitioners. It empowers individuals to protect themselves effectively without requiring years of training or advanced physical conditioning.
Why Defendu Matters Today
In a world where personal safety remains a significant concern, Defendu's timeless principles offer a practical solution for self-defense. Its emphasis on preparedness, confidence, and decisiveness makes it a valuable tool for anyone seeking to enhance their personal security.
By blending the wisdom of traditional martial arts with the pragmatism of modern combat training, Defendu stands as a testament to the enduring importance of adaptability and innovation in self-defense.
Whether you're a civilian looking to enhance your safety, a law enforcement officer seeking effective techniques, or simply a martial arts enthusiast, exploring Defendu offers valuable insights into the art and science of survival.
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