Zen masters are said to have burned statues of the Buddha for firewood and scorned the written sutras.
When Chinese Master Yunmen Wenyan was asked, “What is the Buddha?” he replied, “A dried turd.”

When Linji Yixuan, the eponymous founder of the influential Rinzai school (Linji zong) of Chinese Zen (Chan), was asked what monks should do if they encountered the Buddha, he shouted, “If you meet the Buddha [on the road], kill him!”
In 1964 Ch’unsong -- a modern Korean Zen (Son) monk renowned for his iconoclasm -- was invited to the presidential palace to give a Dharma talk at the birthday celebration of Yuk Yong-su, a devout Buddhist laywoman, the wife of Korean President Park Chunghee.

Zen monk Ch’unsong ascended the dais and sat silently for over a half hour, leaning on his staff. When it was obvious that his audience had lost all patience, he held his staff over his head and shouted:

“This is the day the mother of the First Lady split open her vagina!”

He then descended from the dais and walked off without saying another word. Needless to say, he was not invited back.

A Zen master’s awakening [kensho, satori] is said to transcend all the conventional dichotomies of right and wrong, good and evil, moral and immoral.

Sex with prostitutes?
This goes against Gautama's teaching.
This experience frees him to engage in what the tradition calls “unconstrained conduct” (wu’ai xing), which allows its enlightened monks to do iconoclastic things like frequent bar and brothels (whore houses).
  • [NOTE: "Enlightenment" in Zen (satori or kensho) seems to differ from the Theravada school's understanding, where the historical Buddha called it bodhi, "awakening," complete liberation, the realization of nirvana, the end of all rebirth and suffering.]
The Hongzhou school, on what was then the wild Sichuan frontier of China, was especially known for such iconoclasm; many of the portrayals of Zen masters striking, shouting at, and kicking their students are associated with Hongzhou masters.

Derived from Mazu Daoyi and his successors, the Hongzhou school claimed that all actions were equal manifestations of the enlightened mind and that conventional ethical observances placed artificial restraints on the mind’s free functioning.
Such “unconstrained conduct,” however, was subject to withering criticism by certain other factions within the Zen tradition itself.

Guifeng Zongmi, a successor in the Heze lineage that traces itself back to the Sixth Patriarch Huineng, blasted the Hongzhou school for fostering what he considered to be dangerous antinomian tendencies.

Prof. Buswell on Zen enlightenment
The notion that the vast majority of Zen monks are engaged in unconstrained conduct is not true and belied by the fact that Zen monasteries adhere to strict sets of regulations that the tradition itself developed.

These codes are the so-called “rules of purity,” or qinggui, a genre of Zen literature that was intended to provide an indigenous disciplinary code distinct from the imported monastic discipline of India.

Contemporary practice of Zen Buddhism
The source of many of the qinggui’s rules and regulations, however, is in fact the normative Indian Vinaya [original Buddhist monastic code] tradition.

Quinggui codes cover everything from the monthly and annual celebrations and festivals, down to the minutiae of daily life in the monastery and the specific duties of the monastery’s administrative monks.

In modern Korean monasteries, the daily life of Zen monks is so rigorously structured around the 10 to 14 hours typically allocated to formal sitting meditation (zazen) that they are permitted no time even to read or chant, let alone to hit the local bar.

The “unconstrained conduct” of Zen is a literary trope, not a pervasive practice. It is the exception, not the rule. More