Prediction

Prediction (予測, Yosoku) is the 8th chapter of Volume nine and 78th chapter overall.

Plot
Near, through process of elimination based on what he has seen the notebook do, figures out that the fake rule is the “If you don’t write a name in the Death Note after 13 days, you die” rule.

Near calls L and tells him that he’s caught Mello, but he has escaped. Light is furious that Near might have gotten the chance to question Mello first. Still, Light is skeptical that Mello escaped and thinks that Near let him go. However, Near swears that he escaped and begins to ask L about the existence of shinigamis and their ties to the Death Note. Light doesn’t deny it and tells him that he didn’t divulge those details because he thought Near would never believe him. However, then Near asks him if he knows about a fake rule in the Death Note. Light is forced to admit that through process of elimination, it is only logical that the “13 day” rule is the fake one. However, Light suggests that Mello may have been lying and asks Ryuk if all of the rules are true. Ryuk says yes. Excited at the new lead that he has been given, Near asks the new L and the whole Kira investigation team if they had ever seen L’s face. Light panics and hangs up. Near takes it as an affirmative answer. The rest of the investigation team members are angry that Near suspects that one of them is Kira. However, Light decides to call Near back and continue the interrogation. Light admits that they have seen his face. Near then asks them why has Kira, after killing L, not killed the rest of them as well. Telling them that he believes Mello over a shinigami, Near insists that the “13 day” rule is a fake and that Kira is among them, making the shinigami lie. Near even suggests testing the rule by having him write Mello’s name on the Death Note, and if he dies after 13 days, Kira will be happy. Light consults with the investigation team, and they all agree that they do not trust Near enough to go along with such a plan, especially if he thinks that Kira is among them. When Light tells him that they refuse, Near answers that it’s what he expected.

Light now knows that Near suspects him of being Kira and that whole conversation was an act so that he can get the whole investigation team to have doubts about him.

He tells the team that because Near is fishing for information, then Mello can’t be too far behind. He’d probably try to contact Mogi. Just then, Mogi’s phone rings, and Mello is on the other line.

Conception
Ohba said that the chapter's title "Prediction" relates to the predictions made by Light and Near in the chapter. Light predicted that Mello would try to contact one of the task force members, and then Near predicted that the 13-day rule is fake and also that the original task force members have met the original L.

Ohba explained that he made many of the predictions correct so that it would make the plot move forward a lot more. Ohba believed that the story would in fact not "work as well" if the predictions tuned out to be wrong.