Atkinson's flexible firm model analyses the segmentation of the workforce utilising the concepts of core and periphery. This model offers a starting point for examining the segmentation of Japan's labour market but provides little direction in the exploration of why women are predominant in the part-time workforce. The disparity in employment conditions between female and male workers in the periphery is fostering the development of a gender hierarchy in Japan's non-full-time workforce resembling that existing in 'lifetime' employment practices. This raises questions which challenge the applicability of a model for analysing part-time work in Japan, which ignores a consideration of the gender contract.