According to Imi Lichtenfeld, Krav maga is based on certain principles:
" The very essence of krav maga is literally " fight with contact ", rests on seven principles. a somewhat generic principle, i.e., prevention - to avoid being in dangerous situations. For example when hitch-hiking, to avoid unwholesome individuals; when walking, to avoid dangerous neighbourhoods. Secondly, Krav Maga is based on the human body's natural reflexes. Thirdly: Starting from whichever position one is, in to defend and attack along the shortest distance and to favour methods which involve minimum personal risk.
Fourth principle: To attempt to discourage one's opponent verbally bearing in mind the actual situation, its requirements and the danger presented.
Fifth principle: to attack the weak areas of the human body (the eyes, the throat) in order to strike or to subdue one's opponent;
Sixth principle: to try to use any object within one's reach as well as the body's natural weapons;
Finally the last principle, the most realistic principle: no holds barred, no boundaries as to the techniques employed, nothing is forbidden, all strikes are legitimate."
A self-defence system which therefore leaves much to the imagination, and which may also be practised as a sport. "
So really, any technique which is fast, effective and preserves the practitioners integrity and security may be incorporated into KM. However, Imi did devise a six belst system based on the judo colors. This can be examined on
http://www.krav-maga.net/uk/ and search 'technical programs'