If you make 72,000,000 円 a year living in Japan, you will be taxed 29,356,858 円. That means that your net pay will be 42,643,142 円 per year, or 3,553,595 円 per month. Your average tax rate is 40.8% and your marginal tax rate is 45.3%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of 100 円 in your salary will be taxed 45.30 円, hence, your net pay will only increase by 54.70 円.
A 1,000 円 bonus will generate an extra 547 円 of net incomes. A 5,000 円 bonus will generate an extra 2,735 円 of net incomes.