["The Japanese Economic Review, EarlyView. ", "\nIn this study, we empirically tested Mincer's (1962) hypothesis that an observed higher labour supply elasticity for married women than for men or single women is due to their longer household production hours, which are highly substitutable with working hours. Using a time‐use survey of Japanese working married women and an exogenous income tax shock that formed a natural experiment, we found that when taxes decreased, married women in Japan increased their working hours and decreased their hours of household production, with an estimated compensated wage elasticity of market work of 0.13 to 0.30 and of housework −0.31 to −0.02. The results, particularly the near perfect substitutability of household and market work, confirm Mincer's hypothesis.\n"]