Rinzai Zen is a school of Zen Buddhism that emphasizes direct experience and the attainment of enlightenment through meditation and insight. It originated in Japan in the 12th century and is known for its use of koans, which are paradoxical questions or statements designed to provoke deep thought and challenge conventional thinking. Practitioners of Rinzai Zen often engage in seated meditation, known as zazen, and may participate in intensive training sessions called sesshin. The goal is to achieve a sudden realization of one's true nature, leading to a deeper understanding of existence and the interconnectedness of all life.