3.1 Opposition division's communications 

In examining the opposition, the opposition division will invite the parties, as often as is necessary, to clarify the substance of the case, to file observations on communications from another party or issued by itself (see E‑II, 1) and, where appropriate, to adduce evidence in respect of matters under dispute. Rule 81(2) does not require the opposition division to set a period for replying to this invitation. Such a period will, however, be set whenever the opposition division considers this expedient. As regards the length of the period see E‑VIII, 1.2, as regards the extension of a period see E‑VIII, 1.6, and as regards late submission of observations see E‑VIII, 1.7 and E‑VIII, 1.8, as well as Art. 114(2).

Communications from the opposition division and all replies thereto must be communicated to all parties.