Krav Maga (lit. "contact combat") is a military self-defence and fighting system developed for the Israel Defense Forces (IDF) and Israeli security forces derived from a combination of techniques sourced from boxing, wrestling, aikido, judo, and karate along with realistic fight training. Krav Maga is known for its focus on real-world situations and its extreme efficiency. It was derived from the street-fighting experience of Hungarian-Israeli martial artist Imi Lichtenfeld, who made use of his training as a boxer and wrestler, while defending the Jewish quarter against fascist groups in Bratislava, Czechoslovakia, during the mid-to-late 1930s. In the late 1940s, following his migration to Israel, he began to provide lessons on combat training to what was to become the IDF. From the outset, the original concept of Krav Maga was to take the most simple and practical techniques of other fighting styles (originally European boxing, wrestling, and street fighting) and to make them rapidly teachable to military conscripts. Krav Maga has a philosophy emphasizing aggression, and simultaneous defensive and offensive maneuvers. Krav Maga has been used by the Israel Defense Forces' special forces units, security forces and by regular infantry units. Closely related variations have been developed and adopted by Israeli law enforcement and intelligence organizations. There are several organizations teaching variations of Krav Maga internationally.