Article 12-(3). The provisions of the Law relating to Prohibition of Private Monopoly and Methods of Preserving Fair Trade, and the Trade Association Law shall not apply to any of the following acts;provided, however, that this shall not apply to cases where unfair method of competition is employed, where competition in a particular field of trade is substantially restrained by mutually employing undue restrictions on business activities, or where the interests of the person effecting insurance or the insured is unduly injured by substantially restraining competition in a particular field of trade: