Seal script, which had evolved slowly in the state of Qin during the Eastern Zhou dynasty, became standardized and adopted as the formal script for all of China in the Qin dynasty (leading to a popular misconception that it was invented at that time), and was still widely used for decorative engraving and seals (name chops, or signets) in the Han dynasty period. However, despite the Qin script standardization, more than one script remained in use at the time. For example, a little-known, rectilinear and roughly executed kind of common (vulgar) writing had for centuries coexisted with the more formal seal script in the Qin state, and the popularity of this vulgar writing grew as the use of writing itself became more widespread. By the Warring States period, an immature form of clerical script called "early clerical" or "proto-clerical" had already developed in the state of Qin based upon this vulgar writing, and with influence from seal script as well. The coexistence of the three scripts small seal, vulgar and proto-clerical, with the latter evolving gradually in the Qin to early Han dynasties into clerical script runs counter to the traditional belief that the Qin dynasty had one script only, and that clerical script was suddenly invented in the early Han dynasty from the small seal script.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What was invented in the early Han dynasty from the small seal script?
clerical script