①In the case where a person who has acquired property by inheritance or bequest is a person other than a blood relative in the first degree of the decedent relating to that inheritance or bequest (including a lineal descendant of the decedent who has become an heir by representation because a lineal descendant of the decedent died on or before the commencement of the succession or lost the right of inheritance) or the decedent's spouse, the amount of inheritance tax for that person is, notwithstanding the provisions of the preceding Article, the amount calculated pursuant to that Article plus an amount equivalent to 20 percent thereof.

②The blood relative in the first degree in the preceding paragraph is not to include the case where a lineal descendant of the decedent referred to in that paragraph has become an adopted child of the decedent; provided, however, that this does not apply where that lineal descendant has become an heir by representation because a lineal descendant of the decedent died on or before the commencement of the succession or lost the right of inheritance.