Who can say “send”? Interface knowledge and epistemic jurisdiction in cross-border legal work

Cross-border legal work depends not only on doctrine or local expertise but on judgments that make documents usable at a particular moment. Drawing on participant observation in a mainland Chinese law firm during a cross-border investment and financing transaction, this article examines how lawyers moved documents from working draft to execution, closing and archive. The materials comprise 80 unique emails and 1,550 identifiable internal-chat messages. Analysis follows recurring expressions including “my understanding is”, “in order”, “I’ve confirmed it” and “send”, together with practices of version comparison, certification, signature checking and re-execution. Three findings emerge. First, portable legal forms acquire effect only when reattached to particular legal persons, evidentiary media and jurisdictional requirements. Secondly, chains of confirmation distribute epistemic jurisdiction: authority rests not simply on hierarchy, but on a participant’s warranted position in relation to a document, rule or fact. Thirdly, verification is recursive; each check can produce a new version, task or allocation of responsibility. “Interface knowledge” describes the situated professional capacity to translate jurisdictional difference into an actionable documentary judgment and to authorize the next step. The concept directly shifts attention from the circulation of legal expertise to the organizational production of authority inside contemporary cross-border law-firm practice itself.