We report a measurement of neutrino oscillation parameters with the atmospheric neutrino data collected by the Super-Kamiokande detector. In addition to the SK I-V pure-water phases (6511.3 live days), this analysis includes data from the gadolinium-loaded SK VI phase (564.4 live days), increasing the total exposure by $9\%$ relative to the last published study. The improved neutron tagging efficiency in the gadolinium-loaded Super-Kamiokande was used to enhance the neutrino-antineutrino separation and improve the neutrino direction and energy reconstruction. The sensitivity of the oscillation analysis was further enhanced by implementing a neural network trained to identify tau neutrino events.

We also present a second atmospheric neutrino oscillation analysis, in which the oscillatory pattern of the muon neutrino survival probability is studied directly as a function of the reconstructed neutrino flight length divided by the reconstructed neutrino energy, instead of the zenith angle and visible energy combination, resulting in enhanced sensitivity to the atmospheric $\Delta m^2$ parameter.