Answer: The nuji, a bronze mechanism mounted at the rear of the wooden stock of Han-dynasty crossbows, is one of the earliest mechanical devices used in long-range weapons. Compared with earlier crossbows, Han crossbows featured higher sights with graduated scales, allowing users to accurately determine the relationship between shooting angle and range. This innovation enabled precise targeting and represents the earliest known application of ballistic principles in ancient China.

Image: Official Website of Chengdu Wuhou Shrine Museum