Search for $\Theta^{+}$ via $p(K^{+},\pi^{+})$ reaction at KEK-PS-E559

The E559 aims to investgate the $\Theta^{+}$ via the $p(K^{+},\pi^{+})$ reaction using a liquid H$_2$ target and a high resolution spectrometer, SKS, at the KEK-PS K6 beamline. $\Theta^{+}$ would be identified in the missing mass spectrum with the resolution better than 2 MeV. In order to detect particles decayed from $\Theta^{+}$ and impove the S/N ratio, a large acceptance range counter system is installed in front of the SKS. The commissioning and data-taking just started this May. In this talk, analysis status as well as experimetal purposes and methods will be presented.