HYP2015 is the twelfth one in the series of HYP conferences initiated in 1982 in Heidelberg and held periodically every three years, following the successful 11th HYP conference in Barcelona in 2012. The HYP conference brings together theoreticians and experimentalists working on hadron and nuclear physics with strangeness. The topics of the HYP conference have been extended to related fields such as low-energy aspects of QCD, dense and cold matter, as well as hadronic and nuclear systems with heavier flavors. The main part of the HYP2015 conference is held from Monday morning to Friday around noon at the Tohoku University Centennial Hall (Kawauchi Hagi Hall) located in the city of Sendai, where plenary and contributed talks as well as poster sessions take place. Then it is followed by “discussion session” at a hot spring hotel in Sakunami near Sendai from the late afternoon on Friday until Saturday morning with a limited number of (about 100) participants.