Any error in the translation filed can be corrected at any time during proceedings before the EPO, i.e. during pre-grant proceedings and also during opposition proceedings, bringing the translation into conformity with the application as filed in the original language (e.g. with the originally filed Japanese-language PCT application). This applies similarly to translations filed for Euro-PCT applications upon entry into the European phase (see E-IX, 2.1.2). However, correction of the translation during opposition proceedings will not be allowed if it contravenes Art. 123(3), i.e. if it implies an amendment of the claims which extends the protection conferred.
Unless evidence is provided to the contrary, the EPO will assume, for the purposes of determining whether the subject-matter of the European patent application or European patent extends beyond the content of the application as filed (Art. 123(2)), that the translation filed under Art. 14(2) or Rule 40(3) is in conformity with the original text of the application (e.g. in Japanese). The text of the application as filed however remains the basis for determining the allowability of amendments under Art. 123(2) or the content of the disclosure for the purposes of Art. 54(3) (see G‑IV, 5.1).
The EPO has the discretion to require the filing of a certificate that a translation supplied corresponds to the original text, within a period to be specified (see E‑VIII, 1.2 and E‑VIII, 1.6). An invitation to file the certificate may only be made where the EPO has serious doubts as to the accuracy of the translation. Failure to file the certificate in due time will lead to the document being deemed not to have been received unless the EPC provides otherwise. This partial loss of rights is subject to further processing under Art. 121 and Rule 135.
Certification is not in principle required in respect of the translations of the claims into the other two official languages required under Rule 71(3).