Article 21-3.2 "Corporations, trade unions, employee organizations and other organizations shall not contribute to a person other than political parties and political fund organization. In addition, the upper limit of the total donation by corporations, trade unions to political parties and political fund organizations ranges from 7.5 million to 30 million yen depending on the capital of the corporation". (Source: Political Funds Control Act, 1948 (as amended by Act No. 135 of 2007))
3. Is there a ban on corporate donations to political parties?