It was the opening shot in a campaign to make pure Zen the meaningful alternative to the decadent traditional Buddhism of the aristocracy and the new Salvationist sect of Pure Land. But first the Japanese had to be taught how to meditate, so he wrote a meditation "handbook" that explained exactly how and where to undertake this traditional Buddhist practice. His directions are worth quoting at length.
Now, in doing zazen it is desirable to have a quiet room. You should be temperate in eating and drinking, forsaking all delusive relationships. Setting everything aside, think neither of good nor evil, right nor wrong. Thus, having stopped the various functions of your mind, give up the idea of becoming a Buddha. This holds true not only for zazen but for all your daily actions.
Usually a thick square mat is put on the floor where you sit and a round cushion on top of that. You may sit in either the full or half lotus position. In the former, first put your right foot on your left thigh and then your left foot on your right thigh. In the latter, only put your left foot on the right thigh. Your clothing should be worn loosely but neatly. Next, put your right hand on your left foot and your left palm on the right palm, the tips of the thumbs lightly touching. Sit upright, leaning to neither left nor right, front nor back. Your ears should be on the same plane as your shoulders and your nose in line with your navel. Your tongue should be placed against the roof of your mouth and your lips and teeth closed firmly. With your eyes kept continuously open, breathe quietly through your nostrils. Finally, having regulated your body and mind in this way, take a deep breath, sway your body to left and right, then sit firmly as a rock. Think of nonthinking. How is this done? By thinking beyond thinking and nonthinking. This is the very basis of zazen.10
This first little essay was meant to provide Japan a taste of the real Zen he had experienced in China, and it was the beginning of an astounding literary output. Dogen asserted that since the Buddha had meditated and Bodhidharma had meditated, the most valuable thing to do is meditate. Not surprisingly, he received a cold response from the other schools in Kyoto, both the Tendai sects and the other "Zen" teachers who, like Eisai, taught a "syncretic" Zen of compromise with establishment Buddhism. His rigid doctrine was socially awkward for the syncretic Zen monks at Kennin-ji—who seasoned their practice with chants and esoteric ceremonies—and Dogen finally decided to spare them further embarrassment by retiring to a mountain retreat.
Off he went to another temple, An'yoin, where he began to elaborate on the role of meditation in Zen practice, writing another essay, entitled "Bendowa" or "Lecture on Training," designed to provide a more dialectical defense for zazen. Written in the form of eighteen questions and answers, the "Lecture on Training" was intended to further justify the intense meditation he had described earlier. This essay later became the initial section of a massive book today known as the Shobogenzo (Treasure of Knowledge Regarding the True Dharma), which was guarded as a secret treasure of the Soto school for many centuries.
Question: . . . For most people the natural way to enlightenment is to read the scriptures and recite the nembutsu [Praise to Amida Buddha]. Since you do nothing more than sit cross-legged, how can this mere sitting be a means of gaining enlightenment?
Answer: . . . Of what use is it to read the scriptures and recite the nembutsu? It is useless to imagine that the merits of Buddhism come merely from using one's tongue or voice; if you think such things embrace all of Buddhism, the Truth is a long way from you. You should only read the scriptures so as to learn that the Buddha was teaching the necessity of gradual and sudden training and that from this you can realise enlightenment; do not read them so as to make a show of wisdom with useless intellection. . . . Just to continually repeat the nembutsu is equally useless, for it is a frog who croaks both day and night in some field. . . . They who do nothing . . . more than study the scriptures . . . never understand this, so just stop it and thereby cure your delusions and doubts. Just follow the teachings of a true master and, through the power of Zazen, find the utterly joyful enlightenment of Buddha.11
It is not surprising to find Dogen firm in the belief that meditation is superior to the practices of two competing movements: the traditional sutra veneration of the Tendai sect and the Pure Land schools' chanting of the nembutsu to Amida Buddha. But what about the Rinzai Zen teaching that enlightenment is sudden and cannot be induced by gradual practice? He next attacks this position:
Question: Both in India and China, from the beginning of time to the present day, some Zen teachers have been enlightened by such things as the sound of stones striking bamboos, whilst the color of plum blossoms cleared the minds of others. The [Buddha] was enlightened at the sight of the morning star, whilst [his follower] Ananda understood the Truth through seeing a stick fall. As well as these, many Zen teachers of the five schools after the Sixth Patriarch were enlightened by only so much as a word. Did all of them practise Zazen?