secret history; hidden history; unknown historical facts
Refers to historical facts or narratives that are not widely known, often deliberately concealed or overlooked. Used in academic, literary, or journalistic contexts.
This book reveals the secret history of the Warring States period.
彼は会社の秘史を暴露した。
He exposed the hidden history of the company.
Compound of 秘 (secret) and 史 (history). The exact historical derivation is uncertain, but the combination follows standard Sino-Japanese word formation.