There are no Marquess of Queensberry rules in guerrilla warfare. It's a simple matter of kill, or be killed, capture, or be captured. In this phase of the instruction period, the student is taught the gentle art of murder. The technique of killing or crippling his opponent with his two hands at close quarters. The success of this system of close combat has little to do with size or strength. The larger man here should have little trouble tossing the smaller one around, yet, by the pressure of one finger in the right spot, he is rendered powerless. The same theory applies to all the holds in this course. Most valuable offensive blow at close quarters is the chin jab. The hand is held open at shoulder height and the blow is delivered to the opponent's chin with all the weight of the body in the follow-through. Another excellent weapon is the edge of the hand. Keep the fingers tight together, thumb erect. The blow is a sharp slash with follow through. Apart from the commando knife, which is considered in the later part in the training course, there are several hand weapons of inestimable value in guerrilla warfare. One of these is the kosh, spelled kosh. The hitting end is a lead weight which telescopes into a small cylinder secured up the sleeve by a wrist tong. In preparing for action, the cylinder is dropped into the palm of the hand and the actual blow is delivered as a sidearm throw. Centrifugal force drives the lead weight out to the end of the spring. A properly delivered blow to the side of the head will cause a skull fracture and possibly death. The smatchet is a heavy knife of extreme killing power, beautifully balanced and capable of lethal action either with the point, blade or pommel. The derringer, a tiny single-shot pistol which can be concealed in the palm of the hand, or up the sleeve may be the difference between life and death in an emergency. Most methods of disarming are equally applicable to all types of side arms, but the following are believed to be better adapted to use against the revolver. Here is the simplest defense of all, a quick blow with the edge of the hand across the wrist possibly breaking it. Another disarm from the front: Seize the wrist in one hand and with the other, twist the pistol against your opponent's fingers. In some cases, this maneuver works better: grab the a gun in one hand strike the wrist sharply with the other, at the same time pulling the weapon free. A very simple and effective means of reducing the homicide rate when revolvers are used. Merely touch the cylinder and hold it securely. As long as the cylinder can't turn, the gun can't fire. This is not a good idea if the gun is cocked or of the single action variety.
Actual footage from OSS training videos produced by John Ford.