The research aims to effect of the(Randori) exercises which Addressed to the less privileged side on the level of skillful performance and the effectiveness of the attack for junior of Judo , The researcher The researcher used the experiments method using pre and post measurement, the research community were consisted of the buds judo ( from 11 to 13 years) and they are registered in the Egyption judo federation , .population of the study of samples of the study consisted of (32) of the buds, (8) of them sample ex placatory they were divided the rest(24) players into two groups every one of them are (12) players , The researcher found to some results It was the most important of them, the(Randori) exercises which Addressed to the less privileged side has a positive effect on the level of skillful performance and the effectiveness of the attack attack for junior of Judo .