MITCHELL's theory of ship wave resistance was founded on two simplifying assumptions: neglect of viscosity and the linearisation of boundary conditions. Even at the present state of the theory the only general way to appreciate the full import of these assumptions is the comparison with experiment. However, a recently developed theory and technique of wave analysis permit a detailed examination of wave spectrum in contrast with past experimental investigations which were restricted mostly to a measurement of resistance, and in a few cases of wave profjles. It is, therefore, now possible to check the validity of various proposals for semi-empirical corrections due to viscosity and nonlinearity, originally resulting from attempts to reconcile the measured and calculated resistance. We need refer only to INUI's corrections as they include essentially most former proposals due to WIGLEY, HAVELOCK and others. The present paper begins with a discussion of the pertinence of the proposed method of wave analysis to check the validity of the linearised free-wave and ship-wave theories, and to solve the so-called separation (of viscous and wave drag) problem in ship-model correlation. The basic theory is then outlined, leading to formulas for the determination of wave spectrum and resistance from measured wave profiles either perpendicular or parallel to the direction of motion. Results of experiments with a mathematical model (called Inuid) follow. After establishing the validity of the linearised free-wave theory and the consistency of the results of wave analysis, ship-wave theory and experiment are compared in the INUI's corrections. Whereas the comparison of wave light of resistance appears to vindicate INUI's proposals, the detailed comparison of free-wave spectrum, however, reveals their inadequacy. Further research is necessary, before any final conclusions can be made.