The Bank of Japan injected a lot of money into the economy from 2013 to 2020. They found that the cost of holding money has been low, and it's more expensive to store money than it is useful. The right amount of money to have is 1.2 times the country's total income, but Japan actually has 1.8 times that amount. This means there's a 0.2% loss in welfare. To fix this, the Bank of Japan should reduce the amount of money in circulation by over 30%.