Foreign Tax Deduction
The Foreign Tax Deduction (外国税額控除), is a tax deduction that can be used to offset withholding tax paid to a foreign government. The amount that can be deducted depends on individual circumstances; it is not always possible to deduct the full amount of foreign tax paid.
Adjusted amount of foreign income (調整国外所得金額)
Quoting (note 3) from the NTA's No.12007 Foreign tax credit for residents (emphasis added):
"Adjusted amount of foreign income for the year" means the amount of foreign income for the year. […] If you applied the deductions of carry-over of losses (e.g. net losses, casualty losses, losses from the transfer of listed shares) for the year, the adjusted amount of foreign income for the year concerned shall be prior to applying the deductions. In the case where the amount of foreign source income for the year exceeds the "total amount of income for the year", it shall be equal to the "total amount of income for the year"
In the simplest case of claiming for foreign dividends paid to a tokutei kouza account, this will be the total dividend amount in yen.