Unless otherwise provided, the provisions of Chapter III of the New Act apply to corporation tax for business years of corporations (including associations or foundations without juridical personality prescribed in Article 2, item (viii) of the Corporation Tax Act (Act No. 34 of 1965); the same applies hereinafter) commencing on or after the Effective Date, and with regard to corporation tax for business years of corporations that commenced before the Effective Date, the provisions then in force continue to govern.