student has thoroughly caught the idea he may teach himself much. Both for purposes of self-defence and of increasing muscular strength it is necessary for the beginner to seek, at every possible opportunity, for parts of the body that are vulnerable to pain and paralysis when a proper grip is taken. The essential idea in this work may be gained from the arm trick just described. The student should familiarise himself so thoroughly with every vulnerable locality that he can seize it rapidly and unerringly.
It is a principle of jiu-jitsu that a weaker man should be able to attack a stronger opponent, and to defeat him by the aid of the latter's own greater strength. A little practice with the arm pinch will convince any investigator that when his arm has been seized while in a relaxed muscular state the pain of his opponent's attack will increase as the one on the defensive raises his arm and tautens his muscles. When the student is suddenly attacked, and realises that he is sure to be worsted, it is better to surrender at once and thus escape additional pain. In very few of the Japanese
