Zazen, or seated meditation, is often considered the core practice of Zen Buddhism. It is a form of meditation that involves sitting in a specific posture, usually cross-legged, and focusing on the breath and the present moment. However, while Zazen is primarily associated with Zen Buddhism, it is not exclusive to this tradition.

Zazen can be traced back to the teachings of the historical Buddha, Siddhartha Gautama, who is said to have attained enlightenment while sitting in meditation under a Bodhi tree. This form of meditation was later adopted and developed by various Buddhist traditions, including Zen.

In Zen Buddhism, Zazen is seen as the primary means of attaining enlightenment, or awakening to one's true nature. It is believed that through the practice of Zazen, one can quiet the mind and experience a direct realization of the nature of reality. This is often referred to as "just sitting" or "just being" in Zen.

However, Zazen is also practiced in other Buddhist traditions, such as Tibetan Buddhism and Theravada Buddhism. In Tibetan Buddhism, Zazen is known as "shamatha" or calm-abiding meditation, and is often used as a preliminary practice to cultivate a stable and focused mind. In Theravada Buddhism, Zazen is known as "vipassana" or insight meditation, and is used to develop mindfulness and insight into the nature of reality.

Outside of Buddhism, Zazen has also gained popularity in secular mindfulness practices. The focus on present moment awareness and the cultivation of a calm and clear mind can be beneficial for anyone, regardless of their religious beliefs.

It is important to note that while Zazen may be practiced in various traditions and contexts, the intention and approach may differ. In Zen Buddhism, Zazen is seen as a means to attain enlightenment, while in other traditions it may have different goals or purposes.

In conclusion, while Zazen is most commonly associated with Zen Buddhism, it is not limited to this tradition. It is a form of meditation that has been adopted and adapted by various Buddhist traditions, as well as secular mindfulness practices. Ultimately, the practice of Zazen can be beneficial for anyone seeking to cultivate a calm and clear mind and deepen their understanding of themselves and the world around them.