Zen master Daichi (1289-1366) wrote a verse entitled "Buddha's Birth." This was possibly composed as "Kogo", or Incense Phrases for Buddha's Birthday Assembly, what we call "Butsu Gotan-e".
"In Jambudvipa, there are eighty-four thousand castles.
Without using any weapons such as swords and shields, great peace is created.
We capture Gautama, a daylight thief, alive.
So we do not bother to give him a blow with a stick, as Unmon once said."
In Indian cosmology, Jambudvipa is considered a human world.
It is said to be filled with 84,000 earthly desires which cause us to suffer. These earthly desires are likened to "castles" in this verse. We tend to think that our practice is to attack and destroy those castles, believing that we can never attain awakening unless we extinguish all earthly desires.
The Buddha was born into Jambudvipa in order to teach us that that is not the case. He showed us the way to live in peace without resorting to battle against the castles of earthly desires. He never taught how to invent and use weapons to destroy them. True peace is not possible so long as we rely on weapons.
Chinese Zen master Unmon once blamed the Buddha for tricking us like a wily thief by talking about delusion and enlightenment as if they exist separately. So we started a kind of spiritual war against delusion for the sake of enlightenment. According to Unmon, Gautama made uncalled-for statements only to misguide us to practice as though we were at war. He said, "If I had been there when Gautama was born, I would have given him one fatal blow so as to bring peace back to the people's mind". (Of course he is actually praising the Buddha through an expression of reproach). Zen master Daichi says that if only we can capture the Buddha alive, we need not perform "Unmon's one blow" to the Buddha to correct his error.
How is it possible to create great peace without using weapons? How can we capture the Buddha alive?
The answer is to sit zazen of shikantaza. In zazen we do not fight against whatever happens to us. We do not apply any method or technique as a weapon to win the fight. Instead we simply accept it and naturally let go. Zazen is to "cease fire" and to create a profound peace within oneself and the world.
During zazen, "sitting-buddha" is being actualized in a vivid way with our whole body-mind. In that sense a new Buddha is being born moment by moment. That is how we capture the Buddha alive.
In this verse of celebrating Buddha's birth, Zen Master Daichi points out that the purpose of the Buddha's birth into this world is to show us how to "bring about peace in our life without fighting against our earthly desires." And he suggests we practice and realize it through zazen by which we "capture the Buddha alive." As the sixth descendant of Japanese Soto Zen tradition (Eihei Dogen--Koun Ejo--Tettsu Gikai--Keizan Jokin--Meiho Sotetsu--Gida Daichi), he tries to convey what zazen is all about by describing the significance of the Buddha's birth.
In our Soto tradition, we observe Buddha's Birthday Assembly on April 8th to commemorate his birth. Sometimes it is called "Hanamatsuri", meaning "Flower Festival", because he was born in the flower garden in Lumbini. As well as performing a solemn ritual and sutra chanting, people also ladle ama-cha (a tea prepared from a variety of hydrangea) on a small standing baby Buddha statue in a pavillion with a roof decorated with flowers. It is also a day for us to remind ourselves how lucky we are to be born into this world as a human being, because we can meet with wonderful teachings and practices taught by the Buddha.