Taisen Deshimaru was a Japanese Zen master who is credited with bringing Zen to Europe in the 1960s. He was a student of the renowned Zen master Kodo Sawaki and spent many years studying and practicing Zen in Japan before moving to France to spread its teachings. Deshimaru's main teaching was centered around the concept of zazen, or sitting meditation, as the key practice for achieving enlightenment.

According to Deshimaru, the main purpose of zazen is to quiet the mind and allow one to experience the true nature of reality. This is achieved through the practice of "just sitting," without any attachment to thoughts or desires. Deshimaru believed that our minds are constantly filled with illusions and distractions, and zazen helps to clear away these illusions and reveal the true self.

In addition to zazen, Deshimaru also emphasized the importance of incorporating Zen principles into everyday life. He taught that Zen is not just a practice to be done on a cushion, but rather a way of living and approaching all aspects of life. This includes being mindful and present in all activities, whether it be eating, working, or interacting with others.

Deshimaru also emphasized the importance of discipline and perseverance in the practice of Zen. He believed that true understanding and enlightenment could only be achieved through dedicated and consistent practice. This involved following the strict guidelines of the Zen tradition, such as sitting in the correct posture and following the breath.

Another important aspect of Deshimaru's teaching was the idea of "non-duality." This is the concept that all things are interconnected and there is no separation between the self and the external world. Through zazen, one can experience this non-duality and realize the true nature of reality.

Deshimaru's teachings were not limited to just the practice of zazen, but also included ethical and moral principles. He believed in the importance of compassion, respect, and non-violence towards all beings. He also emphasized the idea of selflessness and letting go of the ego, as these were seen as hindrances to achieving enlightenment.

In summary, Taisen Deshimaru's main teaching was centered around the practice of zazen and incorporating Zen principles into everyday life. He believed in the power of discipline, perseverance, and non-duality to help individuals achieve a deeper understanding of themselves and the world around them. His teachings continue to inspire and guide many in their journey towards enlightenment.