  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.
