The Yuzawa area in Japan hosts an active geothermal field. In this study, we combined magnetotelluric (MT) resistivity measurements, microearthquake surveys, and numerical modelling of fluid flow and heat transport to constrain the potential existence of supercritical resources in the Yuzawa area. The numerical model was calibrated based on geological, geophysical, geochemical, and drilling data, and included an intrusive heat source that was spatially inferred by the MT survey. The quasi-static state model results match the observed temperatures and pressures in exploratory wells, as well as the heat source from surface manifestations. An inferred zone with supercritical temperatures forms beneath a zone of intensive silica precipitation, which coincides with the brittle–ductile transition, as mapped from microearthquake hypocentres. Preliminary production forecasts of the supercritical zone show that the fracture permeability controls the enthalpy and mass flow rate, with increasing permeability leading to a higher mass flow rate but a lower fluid enthalpy. This study contributes to a deeper understanding of the structure and characteristics of supercritical geothermal resources in the Yuzawa area.