  We briefly discuss the impact of initial data from the KEK-to-Kamioka (K2K)
neutrino experiment on the nu_mu-->nu_tau oscillation parameters (m^2,tan^2
psi) currently indicated by the Super-Kamiokande (SK) atmospheric neutrino
experiment. After showing the very good agreement between K2K and SK, we
combine the two separate pieces of information. We find that the 99% C.L. range
for m^2 allowed by SK only, m^2=[1.3, 5.6]x10^-3 eV^2, is reduced to [1.5,
4.8]x10^-3 eV^2 by including K2K data. By halving the uncertainties of the K2K
total rate (with central value unchanged), the m^2 range would be ulteriorly
reduced to [1.8, 4.0]x10^-3 eV^2. Such information appears to be already useful
in planning (very) long baseline neutrino oscillation experiments.
