  The KOTO experiment aims to discover the rare decay $K^{0}_{L}\rightarrow
\pi^{0} \nu \bar{\nu}$ at J-PARC. This mode breaks the CP symmetry directly and
is highly suppressed in the Standard Model. Thus the mode is sensitive to new
physics, in particular to the models related to CP violation.
  We performed the first physics run in May 2013. Although the data taking was
terminated after 100 hours due to an accident, the single event sensitivity for
the $K^{0}_{L}\rightarrow \pi^{0} \nu \bar{\nu}$ decay reached
$1.29\times10^{-8}$, which was comparable to the sensitivity of the prior
experiment. We observed one candidate event while $0.36\pm0.16$ background
events were expected.
