written history; historical record
Archaic literary term for written history or historical records, derived from the practice of scraping sweat off bamboo slips before writing. Not used in modern everyday Japanese.
The word 汗青 comes from the old Chinese practice of wiping sweat off bamboo slips before writing on them.
From Chinese 汗青 (hànqīng), literally 'sweat green', referring to the process of preparing bamboo slips for writing by scraping off the green outer layer and wiping away moisture (sweat). The term came to mean 'historical record' or 'written history'.