China’s expansion of its rare earth export controls appeared to mark another escalation in the US-China trade war last week. But the announcements were also significant in another way: unusually, the documents could not be opened using American word processing software.

For the first time, China’s Ministry of Commerce issued a slew of documents that could be directly accessed only through WPS Office – China’s answer to Microsoft Office – as Beijing continues its tech self-reliance drive.

Developed by the Beijing-based software company Kingsoft, WPS Office uses a different coding structure to Microsoft Office, meaning WPS text files cannot be opened directly in Word without conversion.

Previously, the ministry primarily released text documents in Microsoft Word format.