Si Chuan Fei Shi (四川飛石)

Drawing of a Si Chuan Fei Shi, from 'Zhan Shou Quan Shu (《戰守全書》)'.

Si Chuan Fei Shi (四川飛石, lit. 'Sichuanese flying stone') is a type of lightweight, two-man operated traction trebuchet. True to its namesake, the trebuchet was commonly found in Sichuan, although it was also manufactured in Beijing during the twilight years of the Ming Dynasty.

Unlike other Chinese trebuchets, Si Chuan Fei Shi has a A-shaped arm mounted on a single pole, which allows it to be propped on narrow places and pivot easily. This is presumably an adaptation to the mountainous, narrow and uneven terrain of western Sichuan, where many Tusi mountain fortresses stand.