  First, technically there are multiple versions of the Wang Bi and Heshanggong Laozi—over thirty Heshanggong versions are extant—but the differences are on the whole minor. Second, the Wang Bi and Heshanggong versions are not the same, but they are sufficiently similar to be classified as belonging to the same line of textual transmission. Third, the Wang Bi and Heshanggong versions that we see today have suffered change. Prior to the invention of printing, when each manuscript had to be copied by hand, editorial changes and scribal errors are to be expected. In particular, the Laozi text that now accompanies Wang Bi’s commentary bears the imprint of later alteration, mainly under the influence of the Heshanggong version, and cannot be regarded as the Laozi that Wang Bi himself had seen and commented on. Boltz (1985) and Wagner (1989) have examined this question in some detail.