Mondo
Sanzen
Sanzen also called Dokusan, is when a student goes to the Zen master for instruction (Mondo). This is often done twice a day in a monastic temple, or during meditation sessions in Layman-temple.
Typically, this is a confession session, where the student sits before the master to speak of what is blocking them from Enlightenment.
Sometimes the master may ask a question, in the Socratic Method, to help the student break through the hindrances and delemeas.
The Zen Master is suppose to be representing the Cosmic-Buddha, and the student needs to treat the master as the Cosmic-Buddha.

Mondo is not a psychological therapy
Many Zen students tend to use the Zen Teacher, and the Zen Center, as an FREE psychological outpatient clinic, where they speak of all their worries, daily problems, work issues, and complaints about other Zen students. Yes, this is the wrong use of mondo!
It is true, that some Zen Centers are more ‘Zen-like’ in style and cultural appropriation, but are not actually Zen Centers at all. There you will see that the agenda is to cater to the psychological needs of the members, rather than spiritual growth and awakening.

Dharma Combat
Sometimes the Zen teacher may ask senior students to informally use Zen Debate (shosan) with junior students as a means to sharpen their understanding in the basics of Zen and the Buddha’s teachings.
In the Linji lineage, the Rinzi school and the Korean Kwan Um, the use of Zen Debate is key in the understanding of the teachings, as well as in the development of the zen pupils. The debates are essentially the Socratic Methodology in action.

Tibetan Debates
The purposes of Tibetan monastic debate are to defeat misconceptions, to establish a defensible view, and to clear away objections to that view.
These debates can be quite fierce, with name calling, insults, shouting, hitting, and pushing.
The debaters are seeking to understand the nature of reality through careful analysis of the state of existence of ordinary phenomena, the basis of reality. This is the essential purpose for religious debate.

The debate is essential
Many western Zen schools do not permit any formal debate, among the students or even with the teachers. In my own discussions with the Zen teachers about this issue, they informed me that the education and the level of emotional control of most of the students was simply at such a poor level, that debate was not possible.
Furthermore, a Western Tibetan teacher who ran a large monastery in France, once told me that the issue with mental illness among the students was greatly concerning to the point where he no longer could determine if the student was having a spiritual issue or psychological episode.
There are informal debates, I have witnessed and attended many, where the students would gather secretly and debate. Of course, this was in Zen centers where debate was not permitted by the teachers.
Clearly, debate is essential for spiritual growth. The need to test one’s understanding, to root out ones owns misconceptions is an undeniable urge. The debate seems to find its own way to happen, even when it’s against the Zen center rules!