Abstract: In 2018, discovery of the ancient battlefield of the late Ming Dynasty at the river mouth of Pengshan County, Sichuan Province was listed among the “Top Ten National Archaeological Discoveries of 2017”, putting an end to the multiple-dynasty-long mystery of whereabouts of the silver sunk more than 370 years ago. To this discovery unofficial historical records did contribute, but being unofficial means that their credibility is questionable. After reading through the extensive, inter-contradictory unofficial historical records related to “silver sunk at the river mouth” with references of historical relics, the authors first list 10 major unanswered questions, then proceed to suggest some principles to follow and four inter-attestation dimensions-unofficial historical records, official history, underwater discovery and documents-to observe when accepting unofficial historical records as true.

Key words: silver sunk at the river mouth, dual attestation, unofficial historical record, private notes