(Jap.; Chin., kung-an).
Sometimes referred to as ‘zen riddles’, kōans are brief stories or dialogues from the Ch'an/zen tradition upon which Zen students focus during their meditation in order to penetrate their meaning. During the late T'ang and early Sung dynasties in China.the Ch'an community experimented with many new teaching methods that would allow masters to directly elicit an experience of awakening (Satori) on the part of their students. These ‘shock Ch'an’ or ‘crazy Ch'an’ techniques included beating, shouting directly into the student's ear, or giving paradoxical or nonsensical responses to their questions. Later, during the mid- to late Sung period, stories of master–student encounters that had succeeded, or simple tales of a master's strange behaviour, circulated within Ch'an circles in the form of ‘sayings of the master’ or ‘transmission of the lamp’ (Chin., ch'uan teng lu) literature. Examples included the Record of Lin-chi (Chin., Lin-chi lu) and the Patriarchs' Hall Anthology (Chin, Tsu t'ang chi). As students reflected upon these stories, they found that they could use them as helpful devices in their own meditation. In reading the story of a master whose teaching methods had led a student to enlightenment (bodhi), they could ask themselves: what was the master's mind at that moment? What did the student experience? In other cases not involving the recounting of an enlightenment experience but simply giving an instance of a master's teaching or even a casual dialogue, the student could try to break through the obstructions in their own mind that kept them from directly experiencing their own nature and seeing their own inherent enlightenment. The formal use of such stories as a teaching device for students is first mentioned in connection with Nan-yüan Hui-yung (d. 930).
Fen-yang Shan-chao (942–1024) of the Lin-chi school was the first to compile an anthology of kōans, many of which he composed himself. These appear in the middle volume of the Record of Fen-yang (Chin, Fen-yang lu). Subsequently, many Sung-period masters of the Lin-chi school excelled in the use of kōans and in the contrivance of situations later enshrined in kōans. However, two anthologies of kōans stand out in the Ch'an tradition. The first is the Blue Cliff Records (Chin., Pi-yen lu; Jap., Hekigan-roku), first compiled by Hsüeh-tou Ch'ung-hsien (980–1052) and later expanded by Yüan-wu K'o-ch'in (1063–1135). Hsüeh-tou had compiled the hundred cases comprising the work and added his own verse to them, while Yüan-wu added an introduction and commentaries to the case and Hsüeh-tou's verse to each case. The second is the Wu-men kuan (Jap., Mumonkan; see Gateless Gate), a collection of 48 cases compiled by the monk Wu-men Hui-k'ai (1183–1260) that appeared in 1229. The title could mean ‘Wu-men's Pass’ or ‘Wu-men's Barrier’, but a play on the meaning of the characters of Wu-men's name also make it possible to give it the more paradoxical translation the ‘Gateless Gate’ or ‘The Pass with No Door’. The kōans included in this text are stripped of all but the most essential elements in order to confront the student with the pith of each story. While other kōan collections have appeared through the years, these two have enjoyed the greatest status, serving as textbooks in kōan training. Use of kōans has been mostly been the province of the Lin-chi school (and its Japanese successor, the Rinzai school), while the Ts'ao-tung (Jap., Sōtō) has tended to downplay their use, seeing kōan practice as an artificial effort to attain Buddhahood, to which they oppose simply sitting in meditation as a more direct experience of Buddhahood. Even within circles that made use of them, kōan practice has received criticism for encouraging mere cleverness and wordplay rather than genuine enlightenment.and periodically answer-books have appeared purporting to give students an easy way to pass through the ‘curriculum’ and gain credentials.