Sosan, also known as the Third Zen Patriarch, was a Chinese Zen teacher who played a significant role in the development and spread of Zen Buddhism in other countries. His teachings had a profound impact on the growth of Zen in other countries, particularly in Japan and Korea.

One of the main ways in which Sosan's teachings influenced the development of Zen in other countries was through his emphasis on the practice of meditation. Sosan believed that meditation was the key to attaining enlightenment and that it was essential for all practitioners to cultivate a deep and focused meditation practice. This emphasis on meditation became a central aspect of Zen in other countries, where it became known as "zazen" or "sitting meditation." Sosan's teachings on meditation also influenced the development of other forms of meditation, such as koan practice, which became an integral part of Zen in Japan.

Sosan's teachings also had a significant impact on the development of Zen in Japan. In the 12th century, the Japanese monk Dogen traveled to China to study Zen under the guidance of Sosan's disciple, Rujing. Dogen was deeply influenced by Sosan's teachings, particularly his emphasis on the practice of zazen. Upon returning to Japan, Dogen founded the Soto school of Zen, which became one of the major schools of Zen in Japan. Sosan's teachings also influenced other Japanese Zen masters, such as Hakuin and Bankei, who further developed and spread Zen in Japan.

In Korea, Sosan's teachings were transmitted through the teachings of his disciple, Puji. Puji's teachings, which emphasized the practice of meditation and the attainment of enlightenment, became the foundation of the Korean Seon school of Zen. This school became one of the major branches of Zen in Korea and had a significant impact on the development of Korean Buddhism as a whole.

Furthermore, Sosan's teachings also influenced the development of Zen in other countries, such as Vietnam and Tibet. In Vietnam, Sosan's teachings were introduced by the Chinese monk Thien Minh, who founded the Thien school of Zen. In Tibet, Sosan's teachings were incorporated into the teachings of the Tibetan master, Milarepa, who is considered one of the greatest yogis in Tibetan Buddhism.

In conclusion, Sosan's teachings had a profound influence on the development of Zen in other countries. His emphasis on meditation and the attainment of enlightenment became the cornerstone of Zen practice in other countries and continues to be a central aspect of Zen Buddhism today. Sosan's teachings also helped to shape the various schools and traditions of Zen in other countries, making him one of the most influential figures in the history of Zen Buddhism.