Tokai-to-Kamioka (T2K) is a long-baseline neutrino oscillation experiment currently ongoing in Japan. T2K has been the first experiment to detect the appearance of electron neutrinos in a muon neutrino beam and is now heading towards a quantification of the CP violating phase in the leptonic sector: δCP. The T2K Collaboration has recently published in Nature very exciting results showing the strongest constraint yet on δCP which governs the breaking of the symmetry between matter and antimatter in neutrino oscillations. For the first time, T2K has disfavored almost half of the possible values at the 99.7% (3σ) confidence level. This outstanding result is starting to reveal a basic property of neutrinos that have not been measured until now. This is an important step on the way to knowing whether or not neutrinos and antineutrinos behave differently. I will present in detail these new results paying attention to the description of all elements involved in the analysis.