Whenever Sou displays his knowledge on any of a variety of subjects most of which are college-level courses which noted on the main page is accurate (if a little out-dated at times).
Sou outwitting notorious criminals who continuously escape law by manipulating them using their own behavioral pattern is always awesome and cathartic.
Metawise: The series, along with C.M.B. and Rocket Man basically have the Mystery of the Week be an excuse to explore various fields of science, math, history, etc. Keep in mind Q.E.D.'s demographic is between 12-18 meaning the author is basically teaching subjects like basic quantum physics to middle-high schoolers.
Original Series
As elaborated in the Action Girl entry, Kana, with Nanase, can thrash the whole squad of desert raiders empty-handedly. Bear in mind they are only high schoolers against professional mercenary.
Kana also fought gun-toting diamond-smuggling mafia led by tyrant. In a church. And on its rooftop. With only two wooden sticks. Ran is proud.
A story called Magic and Magic is one of those rare displays when Sou is outwitted by his "opponent," a magician. How, you say? By involving Kana as one of his accomplices! Yes, someone whom Kana and Sou just met was able to deduce that the infallible Sou would not suspect Kana of anything.
Q.E.D.iff
The beginning of the first chapter has Kana helping to recruit first years for the kendo club when a group across from them start arguing about missing fliers and it's to the point that Kana picks up a stone with a plaque on it freaking out a bunch of students. Then Touma comes up and with barely any info figures out what happened to the missing flyers and completely diffuse the situation. More or less giving new readers a general idea of the series.
