  In this article the NA61/SHINE detector will be presented which is a large
acceptance hadron spectrometer at the CERN SPS. It allows for a precise study
of particle production from interactions of a 30 GeV proton beam in a carbon
target in order to predict the neutrino flux of the T2K experiment at J-PARC,
Japan. Requirements for the T2K experiment will be discussed together with the
ongoing NA61 measurements. In particular preliminary NA61 results on pion
production and cross section measurements from the 2007 pilot run will be
shown.
