Yikoei, Buddhadasa's younger brother, returned from studying in Bangkok in1926, and took over the family business, thereby giving Buddhadasa the freedom to follow the custom of temporary ordination in preparation for marriage
On July 29, 1926, he was ordained as a Buddhist monk in order to follow the Thai tradition that every young man must become a monk, and spend some time in a monastery before being considered an eligible for marriage. Buddhadasa was therefore ordained in the Mahanikaya Order at Wat Nok. His monastic name was Indapanyo, meaning one who has wisdom like Indra (god).
Buddhadasa initially intended to remain in the monastery only for the three or four months of the rainy season monastic retreat. He quickly realized, however, that he liked the monk's life, and decided to remain a monk for the rest of his life.
Even before ordination, he already had a good knowledge of the Buddhist texts, from his reading and debates in the family store . So during his first rains retreat at Wat Phum Riang, Buddhadasa gave nightly sermons in which he explained Buddha's teaching in simple language. The young monk also trained himself to preach the Milindapanha texts. People were impressed with his knowledge and skill in preaching. Buddhadasa enjoyed the attention and prestige this brought to him.
At the end of that first rains retreat, he decided that he wanted to remain as a monk. Buddhadasa also developed a love for monastic solitude and because his brother, Yikoei, was managing the family business, Buddhadasa received his mother's blessing and encouragement to remain a monk.
He enjoyed life in the monastery, the camaraderie of the other youth, and his abilities in leadership. As a monk he continued to teach youth of Phum Riang village how to cook. "Sometimes I had to teach the novices and temple boys how to cook properly. They didn't know how. Sometimes, when I was overseeing the cooking, villagers passing the wat would catch a whiff of the curries and couldn't help but stop by to ask for a taste."
One of the great draws of monastic life, for Buddhadasa, was the opportunity to pursue higher education. In 1928, Buddhadasa went to Bangkok to continue his pali studies. He resided at Wat Pathumkhongkha.
In Bangkok, however, he was quickly disillusioned with the life in the big city, and did not find the sort of spiritual education he had expected. He was disappointed with the clerical education of the time and complained that, the monk's never had the opportunity to study the actual Scriptures of Buddhism, but were limited to studying the secondary commentaries.
Most of the learning was rote memorization and study of the Dhammapada commentaries, which are different from, and later than, the Pali cannon.
This together with his disappointment with lax lifestyles of the city monks, in the practice of the vinaya, made him lose interest in pursuing his masters degree. After only two months in Bangkok, Buddhadasa found his studies boring and depressing.
After one year in Bangkok, Buddhadasa took a leave of absence and returned to his hometown of Chaiya, to teach at a newly established school of scripture studies in Wat Phrathat. He also wrote his first book in 1929, a cremation volume for Phrakru Sophanachetasikaram, entitled "Giving Alms."
In 1930, Buddhadasa decided to try the Bangkok curriculum one more time, and returned to Wat Pathumkhongkha in Bangkok.
Rather than relying solely on his classroom studies, however, he studied Pali language with a private tutor. So as his Pali skills grew, he was able to read the actual Pali scriptures, the words of the Buddha. To his growing dismay, he discovered that the teachings of the Buddha were different than the real life Buddhism he saw around him in Bangkok. He began to question what he was learning. The first year he took exams, he got the highest score in the country. The second time he took the test, he failed, intentionally, because he answered what he had actually read in the suttas.
Buddhadasa had gone to Bangkok because he had wanted to get a "real Buddhist education" and had assumed the monks of Bangkok were more advanced. But he became disillusioned when he found that the opposite was true. The rural country monks were more virtuous and wise than the sophisticated city monks.
The Bangkok monks lead luxurious lifestyle, and viewed their education as merely a ladder for upward mobility and increased economic and social opportunity. He was deeply disappointed by the contradiction between the Buddha's teachings he could now read in the original Pali, and the example of the monks.
He believed the Sangha should renew itself through a return to the original practices of primitive Buddhism; the original way of life as laid out in the Pali Canon. He asked whether or not Nibbana was actually possible. And if so, why weren't the monks trying to attain Nibbana? Why wasn't it being taught in the monastic university?
In 1932, Buddhadasa decided to leave Bangkok for good. Upon leaving Bangkok, he wrote in his journal "purity is not the be found in the city" - and he believed he had a better chance of finding it in the forest, like the Buddha. He became a marginal figure, and stayed on the "edge' of the monastic system. Yet it was important to him that he never actually break communion with the traditional practices of Thai Buddhism
His diaries of this year say: "I cannot tell the exact date of my coming back home, but I have definitely changed by view from what I once held. This is because I fortunately found some good scriptures that helped me decide resolutely to leave Bangkok." He wrote a letter to his brother: "I intend to find a retreat far from external and internal disturbances so that I can scrutinize the Dhamma subjects that I have learned and hope to interpret. When I have finished my study, and attained a sufficient grasp of the principles of Dhamma to make sure that my research will not go astray, I will abandon the textbooks then lead an unencumbered life and search for purity and truth. I am looking for a retreat where I can temporarily stay and work with my textbooks. I am totally blind about where, if it is not our home village. Everyone should think of me as if I were not staying in Phum Riang at all. I need someone who will help enhance my chances for study. For boarding, please make little change from before. If nothing is available, cooked rice mixed with a dash of fish sauce will be alright."
"Bangkok