For these reasons, scholars feel that Yung-chia could not have written the Song of Enlightenment. In the final analysis, however, knowing who composed the song and when it was written is not important. What is important is that masters of the Sung dynasty emphasized the greatness of this work, and the Ch'an Buddhism which we practice today dates from the Sung dynasty. The methods of hua-t'ou and kung-an (koan) come from the Sung dynasty, and it was also during the Sung dynasty that Ch'an spread to Japan.

The Song of Enlightenment is priceless because it speaks of daily life activities, proper methods of practice, and proper attitudes while practicing, both before and after enlightenment. In fact, Sung dynasty Master Ta-hui Tsung-kao reported that the Song of Enlightenment was so esteemed by Buddhist practitioners that it was translated into Sanskrit. Whether it is true or not, it says something for the reputation of the song.

My guess is that the Song of Enlightenment was written by Yung-chia during the T'ang dynasty, but was not recognized for its virtues. In subsequent generations, Ch'an masters copied it, and in so doing, added comments and edited it, so that it veered from the content of the original work. Nonetheless, the ideas presented in the Song of Enlightenment are in accordance with the teachings of the Sixth Patriarch.

In the Song of Enlightenment, one theme stands out: reality is defined by two sets of terms: real nature, or Dharma nature; and self-nature, or Buddha-nature.