The end of chapter 5: Someone says: Give me my deposit that is in your possession - and the response is one oath that seems to stand for 5 separate denials. With 4 tannaitic opinions as to when the oath counts for a single oath vs. a group of them -- with 2 different methodologies. And starting chapter 6: with a new mishnah, and a new oath -- issued by the judges. The mishnah is long, reviewing the cases of the chapter... many of which are "modeh be-miktzat" - agreeing to part of the claim, and therefore requiring the oath.