The emperor Qin Shi Huang Di 奏始皇帝 burned to ashes the classical books and asked his Prime Minister Li Si 李斯 to create a one and only official list of characters. Limited to 3,300 characters, this list 三倉 is elaborated with the former existing characters, generalizing the principle of :
"basic phonetic primitive + key"
According to this principle, knowing a list of 56 keys and 57 phonetic primitives would have been sufficient to generate the list (56+57+56x57=3,305). Graphically, the characters, drawn with a brush, had to be written in a standard sized square. This style defines the so-called "small seal" style - 小篆.
7th edition of the list. The number increases to reach 7,800 characters. The central power weakening, pronunciations start to vary according to provinces and careless copies 奇字 ensue ; this entails now interpretation difficulties, although the original was straight forward. 96 A.D. Editing of the posthumous work of Xu Zhen 許愼 : the 説文解字 (ShuShuō wén jiĕzì or せつぶんかいじ) in Japanese) which classified 9,353 characters derived from the Li Si list.