Rule 81

1. The Opposition Division shall examine those grounds for opposition which are invoked in the opponent’s statement under Rule 76, paragraph 2(c). Grounds for opposition not invoked by the opponent may be examined by the Opposition Division of its own motion if they would prejudice the maintenance of the European patent.

2. Communications under Article 101, paragraph 1, second sentence, and all replies thereto shall be sent to all parties. If the opposition division considers this expedient, it shall invite the parties to reply within a period to be specified.

3. In any communication under Article 101, paragraph 1, second sentence, the proprietor of the European patent shall, where necessary, be given the opportunity to amend, where appropriate, the description, claims and drawings. Where necessary, the communication shall contain a reasoned statement covering the grounds against the maintenance of the European patent.