One of the key practices in Rinzai Zen, a school of Zen Buddhism, is shikantaza. This practice, also known as "just sitting," is attributed to the 18th-century Zen master Hakuin Ekaku, who is considered the reviver of Rinzai Zen. Shikantaza is a form of meditation that emphasizes the cultivation of awareness and presence in the present moment.

In shikantaza, the practitioner sits in a cross-legged position, typically on a cushion or mat, with their eyes half-open and their gaze lowered. The focus is on the breath and the sensation of the body sitting, without trying to control or manipulate the breath or thoughts. The goal is to simply be present with whatever arises, without judgment or attachment.

Shikantaza is often contrasted with another form of meditation in Zen, known as koan practice. Koans are paradoxical questions or statements that are used to challenge the logical, thinking mind and encourage a deeper understanding of reality. In contrast, shikantaza does not involve any specific object of focus or inquiry. Instead, it is a form of non-dualistic meditation, where the practitioner aims to let go of any distinction between the self and the object of meditation.

The practice of shikantaza is rooted in the concept of "just this," or "only this." This means that the practitioner is not seeking anything outside of the present moment, but rather fully immersing themselves in it. This can be challenging, as the mind often wants to wander or grasp onto thoughts or sensations. However, through consistent practice, the mind can become more settled and the practitioner can cultivate a sense of deep awareness and presence.

Shikantaza is often described as a "gateless gate," meaning that there is no specific technique or method to achieve enlightenment. Instead, it is a direct and intuitive approach to awakening, where the practitioner simply sits and allows things to be as they are. This can lead to a sense of spaciousness and openness, as well as a deep understanding of the interconnectedness of all things.

In conclusion, shikantaza is a fundamental practice in Rinzai Zen, emphasizing the cultivation of awareness and presence in the present moment. It is a form of non-dualistic meditation that encourages the practitioner to let go of any distinctions between the self and the object of meditation. Through consistent practice, shikantaza can lead to a deeper understanding of reality and a sense of interconnectedness with all things.