Presentation in PDF format What is the case of yibum that could be forced, as yibum does require a level of intent? Several attempts are made to answer this question, most are rejected. From what verse is it derived that one can fulfill yibum even if the act of intercourse was performed unwittingly or under duress? Once the verse is brought, it is questioned by other drashot that are derived from those same words. In the end, the other laws are extrapolated from different verses. If one only engages in the initial part of intercourse with his yevama or with a woman who is forbidden to him, it is considered a valid act of intercourse. From where is this derived? The Gemara brings several options from which to derive it but has a hard time learning from these specific verses to other cases. Rabbi Yona in the end learns it from a woman who is a nidda, combined with a verse at the end of Vayikra Chapter 18 which teaches that all the cases are compared to each other. The Gemara then has to go back to the rejected answers (about his brother’s wife who is compared to a nidda and his father and mother’s sister) and explain what those verses are coming to teach.