Napoleonic Code
The word "roppō" is a slightly adapted form of the word used in Japanese to describe the Napoleonic Code (ナポレオン五法典 Napoleon go-hōten) when it was brought over during the early Meiji period. Although, French Emperor Napoleon enacted five major codes, which were, in Japanese, altogether metonymically referred to as "the Napoleonic Code" (the official name of the Civil Code, the first and most prominent one), the Japanese added to this their own constitution to form six codes in all, and thus it came to be called the "roppō" or "six codes."