In the Yŏlban chong’yo 涅槃宗要, one of Wŏnhyo’s 元暁 commentaries on the Da banniepan jing 大般涅槃経, we can find a parallel passage within his work Yijang ŭi 二障義. Wŏnhyo himself explained that one should refer to the Yijang ŭi. The Yijang ŭi had been lost in early times but a manuscript of this text was discovered in Japan, and the text was published in 1979.
By comparing the parallel passages in the Yŏlban chong’yo and Yijang ŭi, we could clear up two points. First, Wŏnhyo wrote the Yŏlban chong’yo by skipping or changing some phrases or sentences in the Yijang ŭi.
Second, the meaning of some Chinese characters whose meaning was uncertain in the Yŏlban chong’yo could be clarified.
