What is the history of the koan?

The history of the koan is deeply rooted in the development of Zen Buddhism, particularly in China and later in Japan. Here’s a brief overview:

Origins of Koan in China

Zen Buddhism (Chan Buddhism in China) began to take shape in the 6th century with the arrival of the Indian monk Bodhidharma, who is traditionally credited with bringing Zen to China.
The use of "gong'an" (公案), the Chinese term for koan, emerged in the Tang Dynasty (618–907). These were records of sayings and actions of Zen masters, often involving dialogues between masters and students.
The "Five Houses of Zen" (Chan) developed during this period, and each school contributed to the tradition of using these enigmatic stories and questions.