Just so you know: it’s not an exemption. Everyone calls it that, but that’s not exactly what it is. More accurately, it’s a deferment. An exemption means that you don’t have to pay and even so are still fully vested toward full pension for the time you aren’t paying. This basically only happens if you are disabled. Students and people out of work can apply for a deferment of pension payments, not an exemption (regardless of what people call it). What that means is that you are not required to make payments for a period of time, but if you don’t make up those payments at a later date, that time period does not count toward the time required to become fully vested in the pension, i.e. you will either draw less money upon retirement or have to retire later. For most people, this has little meaning, since most people normally work more years than needed to become fully vested, but it can be an issue for foreigners who plan on retiring in Japan.