Wiktionary
closed file
n. (context chess English) A file with pawns of both colors on it.
Usage examples of "closed file".
Hoke typed a short report about finding Rollins, made a Xerox copy of the report for Lieutenant Slater, and then took the closed file into Major Brownley's office.
Impatiently Bond lit a cigarette, pulled his shoulders out of their slouch and slammed the mawkish memories back into their long-closed file.
One point seven seconds later it brought up the closed file of HUMINT personnel reporting to Op-Center from the field.
Its cover was red instead of the official green that signified a closed file.
When Shindo had pressed him, he retaliated by intimating that because Tinh had trespassed it was far better to leave the matter where it lay, in a closed file.