With regard to how income tax should be imposed on gains from the transfer of shares or similar interests, a review is to be conducted, including the question of a shift to comprehensive taxation, together with the review of how income tax should be imposed on interest income based on the provisions of Article 51 of the Supplementary Provisions of the Act Partially Amending the Income Tax Act, etc. (Act No. 96 of 1987), while giving consideration to the state of development of an environment for ascertaining income, such as the question of introducing a taxpayer identification number system, to how the overall tax rate structure, including the level of the top tax rate, should be, and to the relationship with an appropriate withholding system.