Combatives is a United States Army synonym for hand-to-hand combat technique. It encompasses various hybrid martial arts that incorporate fighting techniques from conventional martial arts and combat sports. Unlike combat sports, combatives fighting systems usually have limited sport application, because they often focus on simple self-defense and combat techniques.
Per U.S. Army FM 3-25.150 Combatives:
1-1. Hand-to-hand combat — Hand-to-hand combat is an engagement, between two or more persons, with or without hand-held weapons, such as knives, sticks, or projectile weapons within the range of physical contact.
1-2. Combatives — Combatives are the techniques and tactics useful to Soldiers involved in Hand-to-hand combat. Proficiency in Combatives is one of the fundamental building blocks for training the modern Soldier.
Militaries have long taught unarmed combat, both as conditioning and as a supplement to armed combat. Among the samurai of Japan, such combatives were known as Bujutsu (jujutsu, tantojutsu, bojutsu and so on). Like weapon arts such as kenjutsu, yarijutsu and naginatajutsu, these often were adapted in later stages to cultural or sport forms such as kyūdō, judo, or kendo.
Though technology changed with the emergence of gunpowder, the machine gun in the Russo-Japanese War, and the trench warfare of World War I, hand-to-hand fighting methods such as bayonet remained central to modern military training.
Sometimes called Close Quarters Combat (CQC or close combat), World War II-era American combatives were largely codified by Britons William E. Fairbairn and Eric A. Sykes. Also known for their eponymous Fairbairn-Sykes fighting knife, Fairbairn and Sykes had worked in the British Armed Forces and helped teach the Shanghai Municipal Police (SMP)  quick, effective, and simple techniques for fighting with or without weapons in melee situations. Similar training was provided to British commandos, the First Special Service Force, OSS, Army Rangers and Marine Raiders. Fairbairn at one point called this system Defendu and published on it, as did their American colleague Rex Applegate. Fairbairn often referred to the technique as "gutter fighting," a term which Applegate used, along with "the Fairbairn system."
The prevalence and style of combatives training often changes based on perceived need, and even in times of peace, special forces and commando units tend to have a much higher emphasis on close combat than most personnel, as may embassy guards or paramilitary units such as police SWAT teams.
De-emphasized in the United States after World War II, insurgency conflicts such as the Vietnam War, low intensity conflict and urban warfare tend to encourage more attention to combatives. The general discipline of close-proximity fighting with weapons is often called Close Quarters Battle (CQB) at the platoon or squad level, or Military Operations on Urban Terrain (MOUT) at higher tactical levels. The current Marine Corps Martial Arts Program (MCMAP) replaced the Marine Corps LINE combat system in 2002. The U.S. Army adopted the Modern Army Combatives (MAC) program with the publishing of the 2002 field manual (FM 3-25.150), written by Matt Larsen. MAC draws from systems such as Brazilian Jiu-Jitsu, Muay Thai and eskrima, which could be trained "live" and can be fully integrated into current Close Quarters Battle tactics and training methods.
In August 2007 MAC training became required in every Army unit by Army regulation 350-1 (Training). The Modern Army Combatives Program was adopted as the basis for the Air Force Combatives Program in January 2008.
In 2001, Matt Larsen, then a Sergeant First Class, established the United States Army Combatives School at Fort Benning. Students are taught techniques from the 2002 version of Field Manual 3-25.150 (Combatives), also written by Larsen. The regimen focused on small, easily repeatable drills, in which practitioners could learn multiple related techniques rapidly.
For example, Drill One teaches several techniques: escaping blows, maintaining the mount, escaping the mount, maintaining the guard, passing the guard, assuming side control, maintaining side control, preventing and assuming the mount. The drill can be completed in less than a minute and can be done repeatedly with varying levels of resistance to maximize training benefits.
The Combatives School teaches four instructor certification courses. Students of the first course are not expected to have any knowledge of combatives upon arrival. They are taught fundamental techniques in a series of grappling drills. The basic techniques form a framework upon which the rest of the program can build and are taught as a series of drills, which can be performed as a part of daily physical training. While the course is heavy on grappling, it does not lose sight of the fact that it is a course designed for soldiers going into combat. It is made clear that while combatives can be used to kill or disable, the man that typically wins a hand-to-hand fight in combat is the one whose allies arrive with guns first.
Subsequent courses build upon the framework by adding throws and takedowns from wrestling and Judo, striking skills from boxing and Muay Thai, weapons fighting from eskrima and the western martial arts, all of that combined with how to conduct scenario training and referee the various levels of Combatives competitions.
There are several reasons that the combatives course is taught:
Combatives courses have been taught by the United States Military Academy for its entire history. The Virginia Military Institute also has full-time civilian instructors for Level 1 Combatives that is offered to all students in addition to their mandatory Boxing class. In 2005 the Modern Army Combatives Program began to spread to academia with its adoption at Kansas State University, where there are courses specifically tailored to military personnel (active duty and ROTC) and university athletes, in addition to those available to the general student body .