  Recently the so-called $\Theta^+$ resonance has been reported first from
SPring8\cite{nakano} and many following experiments showed apparent
confirmation of the state. Since $\Theta^+$ exclusively decays into either $K^+
n$ or $K^0 p$, it is explained as the predicted pentaquark state which includes
$ u u d d \bar{s}$ quarks. However, one yet has to obtain consistent picture of
$\Theta^+$ and its quantum numbers. We try to explain $\Theta^+$ in a
conventional picture and show that such picture leads to new predictions on
kaon and pion system.
