  The existence of non-strange partner of pentaquark, the J^p = 1/2^+ narrow
resonance, has been investigated by utilizing kaon photoproduction off a
proton. It is found that the corresponding mass is 1650 MeV and the appropriate
observables for investigating this resonance are the recoiled hyperon
polarization, the beam-recoil double polarization C_x, and differential cross
section at backward angles. Future kaon photoproduction experiments at low
energies should focus on these observables.
