Legalize polygyny for rich men who can financially support multiple wives.
Japan's population decline appears to be caused not by women giving birth to fewer children, but by an increase in the number of childless women. It appears that 1 in 3 women remain childless into their forties, compared to 1 in 20 in prior decades.
Women remain childless for several reasons, but my guess is they can't find a man who can support them financially and/or who they find themselves attracted to.
Japan's population decline appears to be caused not by women giving birth to fewer children, but by an increase in the number of childless women. It appears that 1 in 3 women remain childless into their forties, compared to 1 in 20 in prior decades.
Women remain childless for several reasons, but my guess is they can't find a man who can support them financially and/or who they find themselves attracted to.