  Hadron-physics projects at J-PARC are explained. The J-PARC is the
most-intense hadron-beam facility in the multi-GeV high-energy region. By using
secondary beams of kaons, pions, and others as well as the primary-beam proton,
various hadron projects are planned. First, some of approved experiments are
introduced on strangeness hadron physics and hadron-mass modifications in
nuclear medium. Second, future possibilities are discussed on hadron-structure
physics, including structure functions of hadrons, spin physics, and
high-energy hadron reactions in nuclear medium. The second part is discussed in
more details because this is an article in the hadron-structure session.
