14. Is there a limit on the amount a donor can contribute to a political party during a non-election specific period?

Article 21-3.1, "An individual shall not contribute more than 20 million yen per year to political parties and political fund organiations." 

Article 21-3.2 and 21-3.3 "And as for corporations and trade unions, the upper limit of the total contribution to political parties and political fund organizations ranges from 7.5 million to 30 million yen, which is determined based on the capital of the company or the number of members of the trade union.."

Article 21-3.4 "For the organisation except an individual, corporations, and trade unions, the upper limit of the total contribution to political parties and political fund organizations ranges from 7.5 million to 30 million yen,which is determined based on the expenditure of the organisations."

[description, not direct quote] (Source: Political Funds Control Act, 1948 (as amended by Act No. 135 of 2007))