A high speed computer program for the kinematical analysis of bubble chamber events is described. The program treats individual particle interaction or decay vertices, subjecting the measured variables to the equations of energy and momentum according to the least‐squares criterion. This is done in four different cases in which the problem is overdetermined, and a fifth case is calculated in which the problem is just determined. The adjusted or computed variables corresponding to each particle are obtained in all cases as well as the first‐order error matrices for each type of variable. A connected chain of vertices may be processed in sequence.