This study tried to examine whether Japanese speakers' distinction between countable and uncountable nouns is influenced by attaining proficiency in English.
     An experiment replicating the Imai & Gentner (1997) and the Cook et al. (2006) designs was carried out.  Subjects were presented with three types of items: target items (e.g., hand cream in reverse C-shape), same shape items (e.g., hair gel in reverse C-shape) and same material items (e.g., a pile of hand cream).  They were then asked which of the two alternatives would be the same.
     The subjects were native adult speakers of Japanese with both high English proficiency (e.g., TOEIC 785 or above) and experience of living in English-speaking countries for less than three years.  Due to such restraints, it was difficult to find qualified participants.  Only five participated.  Their responses were random.  Two participants showed material preference, two showed shape preference, and the other showed no preference.  Since the number of the participants was small, arriving at a conclusion was difficult.  Yet it can be meaningful in the future to examine other factors such as higher proficiency levels or how recently participants came back from English-speaking countries to investigate categorization by Japanese L2 users of English.