Seijin is a Japanese coming-of-age ceremony held annually on the second Monday of January. It celebrates young people who have turned 20 years old, marking their transition into adulthood. During this event, participants often wear traditional attire, such as kimono for women and suit for men, and attend ceremonies at local government offices or community centers. The ceremony includes speeches from officials, encouraging the new adults to take on responsibilities and contribute to society. It is a significant cultural event in Japan, emphasizing the importance of maturity and the rights and duties that come with adulthood.