KOTO is an experiment at J-PARC, Japan, looking for the rare KL ? p0 ? ? decay. This decay, together with K+ ? p+ ?? , is one of the golden for studying the origin of CP violation in the Standard Model. Given its small but extremely well predicted branching ratio, it is sensitive to new physics beyond the Standard Model and provides a powerful tool to characterize the interplay between flavor and CP violation. In this talk I will review the physics of the K ? p ?? rare decays and the experimental techniques employed to detect them so far. I will then present the first B(KL ? p0 ? ? )result from KOTO using data collected in a short run in May 2013. Finally I will review the status of NA62 at CERN, an experiment dedicated to the measurement of B(K+ ? p+? ? ) at the 10% level.