Note 2-20

(20) Even if the same amount of deduction is made, the amount of decrease in income tax differs depending on the tax rate applied to the taxpayer. In the case of the deduction of 1 million yen from income, for example, the amount of decrease in income tax for income earners with the applicable tax rate of 37% (total taxable income of more than 18 million yen) comes to 370,000 yen (1 million yen × 37% = 370,000 yen), but for those with the applicable tax rate of 10% (total taxable income of 3.3 million yen or less), it comes to only 100,000 yen (1 million yen × 10% = 100,000 yen).