This paper explores the historical challenge of social inclusion relying on the example of the Japanese social security system. The current public assistance system in Japan is grounded on the Public Assistance Act of 1951, which was originally constituted in 1946 and already declared equal treatment of all citizens. We will focus on a hidden aspect in this introductory period of the public assistance system, the actual situations of people who depend on it. We have digitally restored a survey data for households receiving public assistance. This data was collected in a Japanese prefecture in 1952. The results of this survey indicate that differences in poverty by gender are remarkable. For male householders, the total number of events that caused the onset of public assistance, principally injured or diseases, in 1950 or 1951 was more than that of 1944 or 1945. On the other hand, for female householders, the events of 1944 or 1945 were related to the Second World War, principally the death of male breadwinners, which induced poverty. Moreover, we broke down recipients by gender, age, and household types and revealed, in particular, two facts. First, many widows were receiving public assistance, but not all had lost their spouses in the war. Second, the largest age cluster of recipients was composed of children in the compulsory education age group. The increasing inclusion of the ‘standard’ type of household indicates the success of the Public Assistance Act’s universalism. This digitally restored sample has much potential to provide detailed descriptions of life courses and information on the jobs of household members.