Zen is the normal state: silent, peaceful, unagitated.

Taisen Deshimaru (1914 - 1982) was a Japanese Sōtō Zen[4] Buddhist teacher, who founded the Association Zen Internationale. Born in the Saga Prefecture of Kyūshū, Deshimaru was raised by his grandfather, a former Samurai before the Meiji Revolution, and by his mother, a devout follower of the Jōdo Shinshū[1] sect of Buddhism. Interested in the world, he abandoned his mother's practices and studied Christianity for a long while under a Protestant minister before ultimately deciding that it was not for him either. He returned to his own religion, Buddhism, and eventually came into contact with Rinzai teachings.
Eventually, he also grew distant from Rinzai Buddhism and was unsatisfied by his life as a businessman. In 1935, when he was studying economics in Tokyo, Deshimaru began to practice under Sōtō Zen Master Kodo Sawaki[2].
Deshimaru studied with Kodo Sawaki for fourteen years, until Sawaki's death in 1965. Deshimaru received the monastic ordination shortly before Sawaki became ill, and received dharma transmission[3] at Sawaki's death bed. Sawaki is said to have expressed his wish to spread Zen to other parts of the world on his death-bed, and asked Deshimaru to travel to Europe and spread the teaching.
In 1967, Deshimaru went to Europe and settled in Paris in order to fulfill his master's wish and spread the teachings of Zen. In the 1970s, his mission grew. In 1970 Deshimaru received dharma transmission[3] from Master Yamada Reirin. He became Kaikyosokan (head of Japanese Soto Zen for a particular country or continent) in Europe.

Keep your hands open, and all the sands of the desert can pass through them. Close them, and all you can feel is a bit of grit.’ ~Taisen Deshimaru

[1] Jōdo Shinshū, also known as Shin Buddhism, is a school of Pure Land Buddhism. It was founded by the former Tendai Japanese monk Shinran. Shin Buddhism is considered the most widely practiced branch of Buddhism in Japan, with 20% of the population of Japan identifying membership of the sect.

  [2] Kodo Sawaki (1880-1965) was one of the most prominent Japanese Soto Zen[4] teachers of the 20th century.

"Zen is not a particular state but the normal state: silent, peaceful, unagitated."  Master Taisen Deshimaru

[3] Dharma transmission is a concept within Buddhism concerned with the means by which the integrity of teaching and practice is maintained from generation to generation.[citation needed] It generally signifies one of two related phenomena. It may indicate the recognition by a qualified teacher of a student's attainment of liberation or it may refer to a ceremony  in which authority is bestowed by such a teacher to student (on the basis of this recognition) to become a teacher themselves thus conferring the seal of authenticity of the lineage of succession. Often most associated with the Zen tradition, the concept of dharma transmission also exists in many other Buddhist traditions.

[4] Sōtō Zen or the Sōtō school  is the largest of the three traditional sects of Zen in Japanese Buddhism (the others being Rinzai and Ōbaku). It emphasizes Shikantaza, meditation with no objects, anchors, or content. The meditator strives to be aware of the stream of thoughts, allowing them to arise and pass away without interference.
With about 14,000 temples, Sōtō is one of the largest Japanese Buddhist organizations. Sōtō Zen is now also popular in the West, and in 1996 priests of the Sōtō Zen tradition formed the Soto Zen Buddhist Association based in North America.

To practice Zen or the martial arts, you must live powerfully, sincerely, without reserves, as if you might die in the next instant. Absent this sort of commitment, Zen becomes mere ritual and the martial arts devolve into mere sport.