Zánzhǐ 拶指 is one technique of torture

Torture

Torture is the act of inflicting severe pain as a means of punishment, revenge, forcing information or a confession, or simply as an act of cruelty. Throughout history, torture has often been used as a method of political re-education, interrogation, punishment, and coercion...

 that was used in ancient China

History of China

Chinese civilization originated in various regional centers along both the Yellow River and the Yangtze River valleys in the Neolithic era, but the Yellow River is said to be the Cradle of Chinese Civilization. With thousands of years of continuous history, China is one of the world's oldest...

. 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

KGB

The KGB was the commonly used acronym for the . It was the national security agency of the Soviet Union from 1954 until 1991, and was the premier internal security, intelligence, and secret police organization during that time.The State Security Agency of the Republic of Belarus currently uses the...

 used a variant of this for crushing fingers or toes. The kia quen

Kia quen

In the 17th Century, jiá gùn 夾棍 was reportedly a technique used in China for the interrogation of male suspects without putting their lives in danger....

, 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.)