Except as otherwise provided in these Supplementary Provisions, the provisions of the Corporation Tax Act as amended by the provisions of Article 2 (hereinafter referred to as the "New Corporation Tax Act") apply to corporation tax on income for a business year of a corporation (including an association or foundation without juridical personality prescribed in Article 2, item (viii) of the New Corporation Tax Act; the same applies hereinafter) beginning on or after April 1, 1989 and to corporation tax on liquidation income resulting from a dissolution (excluding a dissolution resulting from a merger; the same applies hereinafter) or merger on or after that date (including corporation tax on income for a business year in liquidation of a corporation subject to corporation tax on liquidation income and corporation tax payable as a result of a partial distribution of residual assets; the same applies hereinafter in this Article), and with regard to corporation tax on income for a business year of a corporation that began before that date and corporation tax on liquidation income resulting from a dissolution or merger before that date, the provisions then in force continue to govern.