This is part of Japan's tax system. If you are not a Japanese tax resident, dividends from Japanese stocks may be taxed differently, or not at all, under the rules of your own country.
How it works
Dividends paid out of corporate profits are, in effect, taxed twice: once as corporate tax at the company level, and again as income tax when received by the individual as dividend income. The dividend tax credit adjusts for this double taxation when comprehensive taxation (see related page) is chosen on a tax return, by allowing an amount calculated under a set formula to be deducted from income tax and resident tax.
Points to keep in mind
The dividend tax credit applies only when comprehensive taxation is selected; it does not apply if separate self-assessment taxation (see related page) or the no-filing option is chosen instead. Which taxation method is most advantageous depends on your income level and other factors, so please confirm the exact tax amount and the best option with the tax office or a qualified tax accountant.