Explain Portias tactics. Why does she appear to support Shylock at first?

When Portia arrives in court, she asks, "Which is the merchant here, and which the Jew?" (4.1.169). Indeed, given the confusion so many people have with the title, it is often this very question which is asked. Scholars have tried to attribute her question to blind justice, arguing that Portia does not want to show any favorites. However, on an Elizabethan stage she would be able to recognize Shylock immediately from his distinctive dress.

Portia then asks Antonio if he confesses to signing the contract. He does, and Portia then says that Shylock therefore must be merciful. She delivers a short speech on mercy, but Shylock ignores it and demands the contract be fulfilled. Portia then asks if no one has been able to repay the amount, but since Shylock has refused the money there is nothing she can do to make him take it. She comments that she must therefore side with Shylock.

Shylock, impressed that Portia is supporting his case, says, "A Daniel come to judgment, yea, a Daniel!" (4.1.218). Portia then rules that Shylock has the right to claim a pound of flesh from next to Antonio's heart according to the bond. Antonio's bosom is laid bare and Shylock gets ready to cut. Portia asks him if he has a surgeon ready to stop the bleeding once he has taken his pound of flesh. Shylock says, "I cannot find it. 'Tis not in the bond" (4.1.257).

Just as Shylock is about to start cutting again, Portia says that the bond does not give him permission to shed Antonio's blood. She has turned the tables, effectivelt saving Antonio.