lü 律, statutes of the legal code

Lü 律 is the common term for premodern Chinese law codes. It was initially interchangeable with the terms xing 刑, meaning "penal law" (see wuxing 五刑 "five capital punishments"), fa 法, which translates to "standards, regulations", and dian 典, meaning "canon".

The term was first used in 359 BCE, when Shang Yang 商鞅 (c. 390-338 BCE) reformed the law in the regional state of Qin 秦. According to the glossary Erya 爾雅, the word lü 律 means "regulated standard or balance" (chang 常, fa 法), expressing the function to standardise the rules for all people. The dictionary Shuowen jiezi 說文解字 states that lü means "spread of equality" (jun bu 均布). The commentator Duan Yucai 段玉裁 (1735-1815) corroborates this by rendering the meaning as "to equalise differences" (fan tianxia zhi bu yi er gui yu yi 范天下之不一而歸於一). The term is also used for the pitch pipes (lülü 律呂, consisting of six lǜ 律 pipes and six lǚ pipes 呂) that helped to determine the proper sound of musical instruments, such as bronze bells. This was achieved by defining the length and volume of the pipes. Shang Yang thus employed the term lü to denote the function of laws in creating balance and fairness in the application of punishment.

Another interpretation of the term is found in the Han-period 漢 (206 BCE-220 CE) glossary Shiming 釋名, which, in accordance with the custom of the time, employs a homophone and clarifies that lü /lǐuět/ 律 signifies lei 累 /lǐwe/ "to gather the people's hearts to avoid presumptuousness" (lei ren xin shi bu fangsi 累人心使不放肆).

In imperial China, lü were the main statutes of the penal code. They were supplemented by ling 令, statutes of the administrative code. The law codes of the first millennium of imperial times are named with the term lü, such as Qinlü 秦律 (see Shuihudi Bamboo Statutes), Hanlü 漢律, Wei xinlü 魏新律, Jinlü 晉律, etc. The combination of lü and ling, known from the Han period on, can be seen in titles like Tang lüling 唐律令 (see Tanglü shuyi 唐律疏義), Kaihuang lüling 開皇律令, Zhenguan lüling 貞觀律令, or the Japanese Taihō ritsuryō 大宝律令.

An essay of Du Yu 杜預 on the law statutes, Lü xu 律序, quoted in the encyclopaedia Taiping yulan 太平御覽, says, the lü (penal law) is used to define crimes, while the ling (administrative regulations) are used to establish governance and procedural rules" (lü yi zheng zui ming, ling yi cun shi zhi 律以正罪名，令以存事制).

The administrative regulations Tang liudian 唐六典 say that "the penal laws serve to standardize punishments and determine crimes" (fan lü, yi zheng xing ding zui 凡律，以正刑定罪).