To benefit from the expected increase of data due to the upgrade of the beam intensity at the T2K experiment the systematic uncertainties of the neutrino oscillation measurements have to be constrained, too.
Systematic uncertainties in neutrino oscillation are dominated by uncertainties related to the modelling of neutrino interactions. To improve the understanding of the nuclear effects an upgrade of the near detector ND280 of the T2K experiment was initiated which will yield better tracking and timing of final state particles. The improvements of the neutrino energy reconstruction based on the new detector capabilities are discussed.

The upgraded ND280 detector will consist of a totally active Super-Fine-Grained-Detector (SFGD) composed of 2 million 1 cm³ scintillator cubes, two High Angle TPC (HATPC) instrumented with resistive MicroMegas, and a surrounding Time-of-Flight (ToF) detector.
It will improve our knowledge of neutrino interactions due to its full polar angle acceptance of the final state particles and a much lower proton tracking threshold.
Furthermore, neutron tagging capabilities, in addition to precision timing information, will allow the upgraded detector to measure neutron kinematics from neutrino interactions.
Such improvements permit access to a much larger kinematic phase space and the analysis of transverse kinematic imbalances, to offer nuclear physics constraints for T2K analyses.
New reconstruction algorithms are being developed to benefit from the improved capabilities of the upgraded near detector.