K2K and T2K

K2K is the first accelerator experiment to investigate neutrino oscillation in the Delta m(2) region of atmospheric neutrinos. The observed energy dependent disappearance of v(mu) leads, with a preliminary analysis of the full statistics, to the determination of sin(2)2 theta = 1.19 +/- 0.23 and Delta m(2) = (2.55 +/- 0.40) x 10(-3) eV(2). The T2K experiment, follow-up of K2K, will start data taking in 2009. T2K will use the new high intensity muon neutrino beam now under construction at J-PARC. Neutrino interactions will be detected, as for K2K, in SuperKamiokande at a distance of 295 km. Main goals of the experiment are a high sensitivity search for v(e) appearance and a study of v(mu) with precision delta(Delta m(23)(2)) similar to 1 x 10(4) eV(2) and delta(sin(2)2 theta(23)) similar to 0.01.