Last fall a single mother living in Osaka started a petition to get the city government to reduce the fees she paid for daycare. Her argument is based on the widow's exemption (kafu kojo), which is granted to certain people on their income tax returns. Though many single parents qualify for the exemption, this woman does not. The exemption only applies to women whose husbands are dead (or missing) or who are divorced, regardless of whether or not they have children.
According to an article in Tokyo Shimbun, the petitioner was engaged to get married, but during her fifth month of pregnancy her fiancee got cold feet and left her. It was too late to get an abortion, so she quit her job in Tokyo and moved back to her parents' home in Osaka. Three months after giving birth she started working part-time, and later secured full-time regular employment. Consequently, her income increased, and thus she had to pay more for daycare since the center where her child was enrolled determines fees based on income.
In Japan "income" (shotoku) is considered to be the amount of money on one's tax return after all exemptions and deductible expenses are subtracted. Because this woman is not a widow or a divorcee, but rather a single mother who has never been married, she doesn't qualify for the exemption, which is either ¥350,000 or ¥270,000, depending on circumstances. And since she can't take the exemption, her income is higher, and thus she pays more for daycare.