The adaptation of Chinese traditions by Koreans and the subsequent influence of Korean culture on Japan occurred over a long historical period, particularly from the early centuries of the Common Era (around the 1st century AD onward). Significant interactions between Korea and Japan took place through trade, cultural exchange, and the transmission of Buddhism, particularly between the 4th and 7th centuries.
During the Three Kingdoms period (approximately 57 BC to 668 AD) in Korea, various aspects of Chinese culture, such as writing systems, Confucianism, and Buddhism, began to take root in Korean society. This cultural exchange continued to evolve and would later play a crucial role in shaping both Korean and Japanese cultures during the Asuka and Nara periods in Japan (approximately 552 to 794 AD).
So, while these cultural exchanges began in earlier centuries, their influences can be seen throughout the development of both cultures well into the medieval period and beyond.