After zazen we bow to the floor nine times. By bowing we are giving up ourselves. To give up ourselves means to give up our dualistic ideas. So there is no difference between zazen practice and bowing. Usually to bow means to pay our respects to something which is more worthy of respect than ourselves. But when you bow to Buddha you should have no idea of Buddha, you just become one with Buddha, you are already Buddha himself. When you become one with Buddha, one with everything that exists, you find the true meaning of being. When you forget all your dualistic ideas, everything becomes your teacher, and everything can be the object of worship.

When everything exists within your big mind, all dualistic relationships drop away. There is no distinction between heaven and earth, man and woman, teacher and disciple. Sometimes a man bows to a woman; sometimes a woman bows to a man. Sometimes the disciple bows to the master; sometimes the master bows to the disciple. A master who cannot bow to his disciple cannot bow to Buddha. Sometimes the master and disciple bow together to Buddha. Sometimes we may bow to cats and dogs.
In your big mind, everything has the same value. Everything is Buddha himself. You see something or hear a sound, and there you have everything just as it is. In your practice you should accept everything as it is, giving to each thing the same respect given to a Buddha. Here there is Buddhahood. Then Buddha bows to Buddha, and you bow to yourself. This is the true bow.

If you do not have this firm conviction of big mind in your practice, your bow will be dualistic. When you are just yourself, you bow to yourself in its true sense, and you are one with everything. Only when you are you yourself can you bow to everything in its true sense. Bowing is a very serious practice. You should be prepared to bow even in your last moment; when you cannot do anything except bow, you should do it. This kind of conviction is necessary. Bow with this spirit and all the precepts, all the teachings are yours, and you will possess everything within your big mind.

Sen no Rikyu, the founder of the Japanese tea ceremony, committed hara‑kiri (ritual suicide by disembowelment) in 1591 at the order of his lord, Hideyoshi. Just before Rikyu took his own life he said, "When I have this sword there is no Buddha and no Patriarchs. " He meant that when we have the sword of big mind, there is no dualistic world. The only thing which exists is this spirit. This kind of imperturbable spirit was always present in Rikyu's tea ceremony. He never did anything in just a dualistic way; he was ready to die in each moment. In ceremony after ceremony he died, and he renewed himself. This is the spirit of the tea ceremony. This is how we bow.