noun
Kōgo register; Japan's first census register (670)
Historical term referring to the family register created in 670 CE, used as a basis for later legal and social status distinctions.
庚午年籍は、天智天皇の時代に作成された日本最初の戸籍である。
The Kōgo register is Japan's first census register, created during the reign of Emperor Tenji.
From 庚午 (kōgo, the 7th year of the sexagenary cycle, corresponding to 670 CE) + 年籍 (nenseki, 'annual register'). The name reflects the year of its creation.