The present paper examines the choice of relative pronouns in the First Quarto and First Folio texts of Shakespeare’s Richard III, with the purpose of testing the adequacy of the memorial reconstruction hypothesis, which Patrick first proposed in his 1936 monograph. He notes a high proportion of corrupted readings in the Quarto, suggesting that it is a re- construction of the Folio, created by actors relying on their inaccurate memories. On the other hand, Smidt (1964) demonstrates that the Quarto’s readings are preferable in many details, though he admits Patrick’s hypothesis, in part, in his second book (1970). Regarding the use of relative pronouns, there is a crucial difference between the two texts: the Folio uses that 13 times to introduce non-restrictive clauses, while the Quarto uses which, and these two items are never substituted the other way around. Interestingly, the Quarto’s choice accords with Shakespeare’s ordinary usage, whereas the Folio deviates from it. Thus, the memorial reconstruction hypothesis cannot explain the variants of relative pronouns. It will be posited that relative pronouns in the Quarto text may have been deliberately revised in the process of written transmission.