b) Grounds not emanating from the board 

Grounds or evidence within the meaning of Art. 113(1) EPC need not emanate from the board, it is sufficient if another party raises the objection (R 2/08; see also R 1/08, R 1/13, R 6/16, R 1/20). If the reason given in a decision corresponds to an argument put forward by the other party, the petitioner was aware of it and thus not taken by surprise (R 4/08, R 12/09 of 15 January 2010 date: 2010-01-15; see also R 8/14, R 8/19, R 1/20), unless the board clearly indicated that it regarded those arguments as not convincing (R 11/12, see also R 6/16). According to the Enlarged Board in R 1/20, that had to apply all the more to the arguments put forward by the EPO. In its decision, the opposition division had explicitly placed the burden of proof on the petitioner. The decision under review had simply confirmed the opposition division's allocation of the burden of proof. The petitioner could have raised all issues relating to the burden of proof at the outset of the appeal proceedings.