One of the reasons given is that they want more revenue from liquor tax, because in 2020 it declined by 10% ($813M). However, considering that it is a “sin tax”, intended to moderate consumption, that is hard to accept.
The real reason is what everyone knows, young people are more likely to hook up if they get drunk. And Japan has a fertility and demographic crisis that no other measures have dented, along with a decline in socialising due to COVID. And a general decline in alcohol consumption has already been happening for decades, down by 1/3 since the mid-1990s.
As reported by the Washington Post:
“Sake Viva!” — a contest run by the nation’s tax agency — is calling on people ages 20 to 39 to come up with “business plans” to help revive Japan’s drinking culture, longan integral part of corporate life in the East Asian nation.
…A 2019 Health Ministry survey found that 29.4 percent of people in their 20s don’t drink alcohol at all, while 26.5 percent said they rarely drink.