Which ruler introduced chain of justice in ancient Tamil?

The chain of justice, known as "Vettiver," was introduced by the ancient Tamil ruler Karikala Chola. He was a prominent king of the Chola dynasty and is known for his progressive reforms, including the establishment of a fair justice system. The chain symbolized the ruler's commitment to justice, where citizens could signal for help if they were wronged. This practice reflected the values of accountability and protection for the subjects under his reign.