Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Q.E.D. ~Shoumei Shuuryou~ is a detective fiction manga by Motohiro Katou. The main character Sou Touma encounters a variety of crimes ranging from murder to fraud. Sou often works in tandem with his friend and potential love interest Kana, with him supplying the brain while she acts as brawn. The manga has a similar structure like Detective Conan and Kidaichi Sh nen no Jikenbo, where time flows forward for the characters (in book 3, Sou gives Kana a pearl necklace as a Christmas present. In book 9, the pair are invited to take part in a mystery game during Christmas) yet the background setting is stuck in time (e.g. Sou and Kana are still in the same grades). The title comes from the Latin phrase quod erat demonstrandum. Sou will typically write the term down when he has solved the case just prior to his explanation. In addition, the manga incorporates many terms and ideas from history, mythology, biology, mathematics and physics.