Zen legend says that one day on Vulture Peak, Shakyamuni Buddha preached a sermon not with words but by holding up a flower. Maha Kashyapa was the only one of Shakyamuni’s many disciples who grasped the true significance of this wordless teaching, which he expressed by a slight smile. Maha Kashyapa thereby inherited Shakyamuni’s robe and lineage as the second Zen ancestor. ...
A special transmission outside the scriptures,
Not founded on words and letters.
Directly pointing to a person’s mind,
One sees one’s nature and become a Buddha.
[translated by Brian Hoffert; cf. Sources of Japanese Tradition, 307]

The Zen lineage was faithfully transmitted in India through twenty-eight generations until Bodhidharma (J: Daruma) brought it to China sometime in the sixth century. (SJT, 306)
This legend is no doubt apocryphal, but for whatever reason a new Chinese interpretation of Buddhism, Chan, coalesced around Bodhidharma’s name. (IJR, 147)

The Second Patriarch
Huike (484-590)

The Sixth Patriarch
Huineng (638-713)
Shenxiu’s Poem
Our body is the bodhi tree,
Our mind a mirror bright.
Always strive to polish it,
And let no dust alight.

Huineng’s Poem
Originally no bodhi tree,
Nor stand of a mirror bright.
Since neither of these things exist,
Where can the dust alight.
(translated by Brian Hoffert;
SJT, 496-8)

Eisai & Rinzai Zen
The first Japanese teacher to discover and transmit this new Chinese Buddhism in the Kamakura era was Myoan Eisai (1141-1215). To be sure, he did not represent Japan’s first meeting with Zen, but no earlier contacts had taken hold. ... Like so many other creators of the Kamakura religious era, the aristocratic Eisai began as a restless Tendai monk. In 1168 his restlessness carried him to China as he embarked with a Shingon priest on a tour of the mainland, intending mostly to sightsee and make a pilgrimage to the main Tiantai temple. The pair was disconcerted to find that once-great monastic center seriously deteriorated. On the other hand, Chan was everywhere. (IJR, 148-9)
During the Song dynasty (960-1279) ... [hagiographical compendiums] depicted the Zen ancestors of all lines as expressing the activity of Buddha awakening in novel ways, with shouts or gestures and strikes and with enigmatic and sometimes impious language. Collections of these individual episodes, known as koan (Ch: gongan), were compiled so that they could be studied as guidelines for Buddhist practice. (SJT, 307)

A monk asked Joshu in all earnestness,
“Has a dog Buddha nature or not?”

Joshu said, “Mu!”
The small rotund monk from Japan was seated high on a vast cushion. He wore a sashed gray robe with wide winglike sleeves, and held a fan in his hand. Taking a note of introduction from my hand, he eyed me shrewdly.
       “So,” he said. “You’re a professor of religion. Do you believe in God?”
       Stumbling around, having no real idea how to express such things to a Zen master, I tried to say something about God as the ground of my being and the source of my life.
       I was cut short. I was surprised by a sting on my thigh as he brought the folded fan down on me. “Not good!” he said strictly. “Now how do you know God?”
       This time I stumbled even more. “Perhaps in the immediacy of the experience ...”
       “Not good!” he retorted, slapping me again with the fan. “This is your Zen koan: Now how do you know God?”
How do I know God before I know I am knowing God, in what the Japanese would call naka ima, the “middle now”? Perhaps the roshi used the term “God” because I was a Westerner; it might have been the Buddha-nature or the Dharmakaya; but the purport was the same. How does the ultimate interface with the passing moment, and how could that be expressed without thinking? How do I push awareness outside the verbal and conceptual boxes into which we put all experiences as soon as we have them, or only a split second later?

I knew that the idea was not to cogitate on the koan, trying to figure it out rationally, but just to hold it in my mind, perhaps just saying it over and over, sinking into deeper and deeper levels of consciousness, until it had an effect beyond the reach of the ordinary mind. Then I began, if only dimly, to have some feeling for the potential of Zen practice. I seemed to be lightly floating, as though a half-inch above the cushion. (IJR, 144-5)
In 1187 Eisai went again to China, this time studying with an aged master of the Linji (Rinzai) lineage on Mount Tiantai. He returned to Japan in 1191 with a certificate of enlightenment. Even so, his commitment was less than total, for he brought an array of other Buddhist and Confucian teachings as well, together with tea plants. ... However, Eisai did establish a Rinzai Zen temple in southern Kyushu .... [He] also got permission to start a Zen temple in the new capital at Kamakura, and later in the old imperial capital of Kyoto as well. He ended his life as abbot there. (IJR, 148-9)

Dogen (1200-1253) was, like Eisai, of aristocratic background. He was the illegitimate son of a Fujiwara mother and a princely father, nurtured and educated amid the elegance of the Old Court. However, his parents both died while he was a child. Thus made acquainted with the dark as well as the sunny side of life, he desired to become a monk. After some difficulty he entered the Tendai center at Mount Hiei.
But like Honen, Nichiren, and others of his age he was troubled by apparent unanswered paradoxes in conventional teaching — in his case the question of why, if a person is born with the Buddha-nature within, does he nonetheless have to seek enlightenment? In this quest, Dogen first worked with a disciple of Eisai, Myozen, in Eisai’s old Rinzai temple, Kennin-ji. ...
The Great Doubt
Both exoteric and esoteric Buddhism teach the primal Buddha-nature [or Dharma-nature] and the original self-awakening of all sentient beings. If this is the case, why have the buddhas of all ages had to awaken the longing for and seek enlightenment by engaging in ascetic practice?
(A Study of Dogen, 19)
Eisai’s Response
All the Buddhas in the three stages of time are unaware that they are endowed with the Buddha-nature, but cats and oxen are well aware of it indeed!
In 1223 Dogen sailed for China with Myozen, desiring to visit Buddhist centers. He found his way to Caodong (Soto) monasteries, where he appreciated the way they emphasized quiet sitting and living Zen in the context of all one’s life, including ordinary labor, more than koans and intense breakthrough experiences. (IJR, 150)

Resolving the Great Doubt
Dogen learned an important lesson, he said, from the aged cook of a monastery who had visited his ship to purchase some Japanese mushrooms. They fell to talking, it became late, and Dogen suggested that instead of walking the ten miles or more back to the monastery, the cook should just stay on board overnight. When the old monk insisted on returning to his duties, Dogen took him to task, saying there must be other monks who could cook, and pressing him on why he wanted to be a cook anyway instead of spending more time practicing zazen. At this the other just laughed, telling the brash young Japanese that if he could ask that, he hardly understood the real meaning of Buddhism. (IJR, 151)
Dogen’s Dharma Master

It was in China, in 1225, that Dogen had his enlightenment experience. While doing early morning zazen, a monk next to him fell asleep. The master, Rujing, walking by, raged,
Zen means the dropping away of mind and body! What will you get by sleeping?”

Dogen was first startled, then felt a tremendous calm and inner joy at these words. He went in to the master who, recognizing him as enlightened, imparted patriarchal succession to the young Japanese. (IJR, 150)

On returning to Japan in 1227 Dogen went first back to Kennin-ji, then lived at other temples, but finally established Eihei-ji, where he was able to lead a temple following his own concept of pure Zen. There he completed his great book, Shobogenzo (Treasure of Knowledge of the True Dharma). (IJR, 151)
The leading Western historian of Zen, Heinrich Dumoulin, has called Dogen “the strongest and most original thinker that Japan has so far produced.” Probably more than any other traditional Japanese intellectual, Dogen would be entitled to take his place as a world-class philosopher. Yet he did not seek fame, nor did he receive much in his own lifetime. All he wanted was to find enlightenment by living a completely natural and ordinary life as a monk. (IJR, 150)
Dogen emphasized in all his philosophical works the unity of practice and enlightenment — and practice is not only meditation, but the whole life of the practitioner: eating, sleeping, working, recreation. Buddhist enlightenment, like that of the old cook, is nothing exotic and otherworldly. It’s just living ordinary life — though in a way in which mind and body are unified, all together in the here and now. Dogen said, “[T]hing of neither good nor evil, right nor wrong. Thus, having stopped the various functions of your mind, give up even the idea of becoming a Buddha. ... Zazen is not ‘step-by-step meditation.’ Rather it is simply the easy and pleasant practice of a Buddha, the realization of the Buddha’s Wisdom.” To become a Buddha, give up wanting to become a Buddha, and be one. (IJR, 151)
“Just Sitting”

In the pursuit of the Way [Buddhism] the prime essential is sitting (zazen). ... By reflecting upon various public cases (koan) and dialogues of the patriarchs, one may perhaps get the sense of them but it will only result in one’s being led astray from the way of the Buddha, our founder. Just to pass the time in sitting straight, without any thought of acquisition, without any sense of achieving enlightenment — this is the way of the Founder. (Religion in the Japanese Experience, 100-1)