Relativistic five-quark equations and a narrow N(1688) resonance

The relativistic five-quark equations are found in the framework of the dispersion relation technique. The five-quark amplitude for the N(1688) resonance including u-, d- quarks is calculated. The pole of this amplitude determines the mass of non-strange pentaquark M=1686 MeV and the width about 7MeV. The results are in good agreement with the evidence for a narrow N(1688) resonance.