Sosan, also known as the Third Zen Patriarch, was a Chinese Zen teacher who lived in the 6th century. He is best known for his famous poem "Hsin Hsin Ming" or "Trust in Mind". This poem is considered one of the most profound and influential works in Zen Buddhism, and it holds deep meaning and teachings for practitioners.

The title "Hsin Hsin Ming" can be translated as "Trust in Mind" or "On Faith in Mind". This title itself holds a key to understanding the meaning behind the poem. Sosan is emphasizing the importance of trusting in one's own mind, rather than relying on external sources for guidance or enlightenment.

The poem itself is a reflection on the nature of the mind and the path to enlightenment. Sosan begins by stating that the ultimate truth is beyond words and concepts, and can only be understood through direct experience. He then goes on to describe the nature of the mind, which is inherently pure and free from any distinctions or dualities.

Sosan emphasizes that the mind is neither good nor bad, and it is only our own attachments and judgments that create suffering. He encourages readers to let go of all concepts and beliefs, and simply trust in the natural state of the mind.

One of the most famous lines in the poem is "The Great Way is not difficult for those who have no preferences". This line speaks to the idea of non-attachment and letting go of our desires and aversions. Sosan is reminding us that the path to enlightenment is not about achieving or attaining something, but rather it is about letting go of all attachments and simply being in the present moment.

Another important message in the poem is the idea of non-duality. Sosan states, "When all things are seen equally, the timeless Self-essence is reached". This means that when we let go of all distinctions and see everything as one, we can reach a state of oneness with the universe.

In essence, Sosan's "Hsin Hsin Ming" is a powerful reminder to trust in our own minds and let go of all attachments and judgments. It teaches us that the path to enlightenment is not about striving or seeking, but rather it is about being in the present moment and seeing the world as it truly is. This message is as relevant today as it was over a thousand years ago when Sosan first wrote this poem, and it continues to inspire and guide practitioners on their spiritual journey.