Japanese Zen is derived from the Japanese pronunciation of the Middle Chinese word 禪 (Chan) which traces its roots to the Indian practice of dhyāna ("meditation"). Buddhism was introduced to China in the first century CE. According to tradition, Chan was introduced around 500 CE by Bodhidharma, an Indian monk teaching dhyāna. He was the 28th Indian patriarch of Zen and the first Chinese patriarch. Buddhism was introduced in Japan in the 8th century CE during the Nara period (710-794) and the Heian period (794–1185). Zen was not introduced as a separate school in Japan until the 12th century during the Kamakura
Doctrinal background of Zen we conceive of is the result of the working of the five skandhas—results of perception, feeling, volition, and discrimination. The five skandhas together compose consciousness. The "things" we are conscious of are "mere concepts", not "Ding an sich". It took Chinese Buddhism several centuries to recognize that sunyata does not refer to "wu", "nothingness", nor does Buddhism postulate an undying soul. The influence of those various doctrinal and textual backgrounds is still discernible in Zen. Zen teachers still refer to Buddha-nature, but the Zen tradition also emphasizes that Buddha-nature "is" sunyata, the absence of an independent and substantial self. In