Tean zu

Zánzhǐ (Pinyin; Wade-Giles romanization, "tean zu") 拶指 is one technique of torture that was used in ancient China. For interrogation of female suspects without threatening life or limb, zánzhǐ was generally applied. It consisted of a set of six wooden sticks positioned around and between the fingers and connected by strings. Each time the prisoner refused to testify or confess, the string was pulled, slowly, agonisingly squeezing the fingers between the sticks until their bones were crushed. The Soviet KGB used a variant of this for crushing fingers or toes. The kia quen, a similar device applied exclusively to men, was used to crush the feet or ankles.

(Reference: Scott, George Ryley. "The History of Torture Through the Ages". London: Kegan Paul, 2003.)