Hakuin Ekaku, also known as Hakuin Zenji, is a highly revered figure in the world of Zen Buddhism. He is considered to be the reviver of the Rinzai Zen tradition, one of the three main schools of Zen in Japan. Hakuin's teachings and writings have had a profound impact on the development and spread of Zen Buddhism, making him one of the most influential Zen masters in history.

One of Hakuin's greatest legacies is his emphasis on zazen, or seated meditation. He believed that zazen was the most direct and effective way to attain enlightenment and encouraged his students to practice it diligently. Hakuin himself spent countless hours in meditation, often in secluded mountain retreats, and his teachings on zazen have been passed down through generations of Zen practitioners.

Hakuin is also known for his skillful use of koans, which are paradoxical questions or statements used in Zen practice to break through dualistic thinking and awaken the mind to its true nature. Hakuin's collection of koans, known as the Hakuin Zenji Zenshu, is still widely studied and used in Rinzai Zen training today. His approach to koan practice was dynamic and creative, often incorporating physical movements and vocalizations, which helped his students to break through their conceptual thinking and experience a direct realization of truth.

In addition to his emphasis on zazen and koan practice, Hakuin also placed great importance on moral discipline and ethical conduct. He believed that true awakening could only be achieved through a combination of meditation, ethical behavior, and the guidance of a qualified teacher. Hakuin himself was known for his strict adherence to the precepts and his uncompromising commitment to the path of Zen.

Hakuin's legacy also extends to his role in reviving and reinvigorating the Rinzai Zen tradition, which had been in decline during his time. He traveled extensively, giving teachings and training monks, and his charismatic personality and powerful teachings attracted many students. Hakuin's influence helped to revitalize Rinzai Zen and establish it as one of the dominant schools of Zen in Japan.

Today, Hakuin's teachings continue to inspire and guide Zen practitioners around the world. His emphasis on the direct experience of truth, the importance of ethical conduct, and the dynamic use of koans are all integral aspects of Rinzai Zen practice. Hakuin's legacy also lives on through his many writings, which are still studied and revered by Zen practitioners of all levels.

In summary, Hakuin Ekaku's legacy in the world of Zen Buddhism is multifaceted and far-reaching. His emphasis on zazen, koan practice, ethical conduct, and his role in reviving the Rinzai Zen tradition have had a lasting impact on the development and spread of Zen Buddhism. His teachings continue to be a source of inspiration and guidance for those seeking awakening and enlightenment.