These street conflicts Imi was involved in were intense and dangerous, frequently leading to deaths on either side. This type of violence was the proving ground for Imi. It was here that Imi learned the stark difference between the Boxing and Wrestling matches of his youth and the life or death nature of of gang violence. Imi later refined these experiences to form the concepts used in the development of Krav Maga. Imi and his activities eventually came to the attention of the authorities and it was only a matter of time for him now. As a marked man Imi had to leave his native country for what was then called Palestine, (now Israel). At 30 years old, Imi left Europe on the last boat to escape the Nazi�??s the Pentcho. Imi was never to see his father alive again.
The Pentcho was a decrepit old River steamer purchased from its Greek owners who called it the Stefano. The Pentcho was moored in, Romania and was awaiting scrapping. It was an elderly River boat with side mounted steam paddles �?? a very old design.The Jewish agents purchasing the vessel registered it under the Bulgarian flag and renamed it Pentcho. The ship was in such poor condition that numerous officials had to be bribed to allow the vessel to comply with various rules as it was not fit to pass any sea worthiness examination. Jewish migrants from all across Europe had gathered in Bratislavia and were attempting to flee the numerous nazi round ups.
Whilst in British Mandated Palestine Imi was introduced by friends to Yitzhak Sadeh, the head of the Haganah. He immediately recruited Imi as an instructor of face-to-face combat because of his widely respected fighting skills. In 1944, Imi began to lead troops in specialized physical fitness training, which included swimming, practical wrestling, and use of a knife and defense against knife techniques. Between 1942 and 1948, Imi supervised the training of the special units of the Haganah, Pal�??mach, Palyam, and of the police forces. This training was called at that time, Kapap �?? an acronym for krav panim l�??panim or face-to-face combat. In 1948 the state of Israel came into existence and was recognised by the United Nations. This event was the motivating force behind the 1948 Arab-Israeli War, a series of armed conflicts between newly formed nation of Israel and its Arab neighbors, who rejected the UN proposition.
Imi joined the newly founded Israeli army in 1948. Here Imi commencing a 15 year period of military service with the IDF. He began to build upon the foundation of fighting principles that were comprised of his boxing, wrestling, gymnastic, and military training. This new fighting style was termed Krav Maga, or contact combat.As the head instructor of Krav Maga for the IDF, Imi had to sift through his own knowledge and experience, as well as the knowledge and experience of his soldiers, to expand the style with the most efficient methods of defence and offence possible. Imis�?? system of Krav Maga had to be fast to learn, simple to use and most importantly, effective for large groups of people with minimal training. In addition, the system had to be suitable for use in the worst possible situations such as when injured, unarmed or at close range with multiple armed attackers. The difficulty of providing this training and the experience and ingenuity required by Imi are hard to overstress.
Lack of resources, including firearms, meant that trainees were taught how to use clubs, knives and even rocks to defend themselves. Imi devised and taught techniques and principles that were easy to learn and easy to apply for new recruits. They also had to be learned in a short period of time and work, even under extreme pressure or disadvantage.