"BLAU" is the 72nd chapter of the Toaru Kagaku no Railgun manga series.
Saten Ruiko meets up with Misaka Mikoto and Shirai Kuroko, the latter still feeling dejected after what happened the night before, and asks Mikoto how she felt about the Indian Poker. Mikoto says it's horrible, confounding Saten as the color of the card should've been that of a happy dream. Saten then states that Indian Poker can be used to learn about new things or skills through dreams, making cards with such dreams very valuable. The people who give out useful, the Dream Rankers, are ranked in a hierarchy, and there are rumours that cards from S-ranks and A-ranks can be sold for lots of money. Saten believes that she can sell cards with her urban legend dreams. She mentions that she came upon another urban legend while looking into this matter, but before she can tell them what it is, she notices Uiharu Kazari nearby. Saten bids them farewell as she goes to her with her usual antics.
Later, Hokaze Junko asks Mikoto what she thought about her Indian Poker card and invites her over for tea. Unable to turn down her sincere kindness, Mikoto accepts. Much to her surprise, however, Misaki has also been invited. The two Level 5s are not amused. Junko reveals that she thought that they could use the chance to deepen their friendship, which both of them immediately reject. Junko tries to continue the conversation, asking Misaki if she knows about the Indian Poker fad going around their group. Misaki says that she is aware of it, so Junko says that Mikoto wants to invite Misaki as well (despite the fact that Mikoto hasn't said anything). Misaki plainly tells her that she is not interested and that Junko and the others should stop using Indian Poker. To Mikoto's surprise, Junko eagerly obeys this order since it came from her "Queen".
Suddenly, there is shouting nearby. At a table of a nearby shop (with shrubs hiding them from view) are Aogami Pierce and three other teens, the latter calling Aogami "BLAU" and thanking him, an S-rank Dream Ranker, for giving them wonderful dreams. One of them, Hikoichi, offers Aogami money in exchange for one of his cards. Aogami declines it, saying that knowing that his dreams give other people happiness is enough to satisfy him, impressing the men, as well as Mikoto (who wonders what kind of dreams Aogami gives to them). However, her impression of him is crushed when she discovers that he sells erotic lewd dreams of various girls, much to Mikoto and Misaki's horror. Junko, however, is apparently too pure and ignorant to understand what they are talking about. Meanwhile, the boys all praise Aogami Pierce for his services, and that it is only a matter of time before his dreams spread into the city. Aogami notes that it isn't just entertainers, and he can dream of the two Level 5s of Tokiwadai, putting both Mikoto and Misaki into a tranquil fury.
As the boys celebrate, the still-clueless Junko praises the two Level 5s for being famous. Mikoto finally snaps, stands up and walks out, saying that she is going to visit the next shop over. Junko is scared of her behaviour and asks Misaki to stop her, but Misaki decides to help Mikoto. Shocked, Junko notes that the two of them can easily pull off the perfect crime.
Mikoto knocks out Aogami's group and destroys their cards, while she and Misaki manipulate the security cameras and witnesses' memories, respectively. Both Level 5s are tense afterwards. Junko tries to lighten the mood by asking them if they have dreams of a gentleman they like. The two Level 5s dodge the question and make up terrible excuses to leave, much to Junko's disappointment.
Meanwhile, Uiharu and Kuroko are in patrol. After Kazari snaps Kuroko out of her daze, she asks Kuroko if she knows of the treasure hunting app, to which Kuroko answers that she does. The app's administrators set points at locations around the city, and people who take photos of those set points using the app's special camera receive a reward. Uiharu adds to Kuroko's explanation: when taking a picture using that app in a certain location, instead of treasure, it apparently shows images of an accident that has happened at the location. Uiharu shows an example on a set of stairs where an accidental fall had occurred. Kuroko remarks that it is in bad taste, but Uiharu reveals that the app also shows accidents that can happen in the future.
- Mikoto and Misaki successfully stop the spread of Aogami Pierce's erotic dreams of their persons via Indian Poker, by destroying his cards and manipulating his memories.
- There is a treasure hunting app that is going around Academy City that can show where an accident is about to occur.
By order of appearance:
- Misaka Mikoto
- Shirai Kuroko
- Saten Ruiko
- Uiharu Kazari
- Hokaze Junko (unnamed)
- Shokuhou Misaki
- Aogami Pierce
- Fugu Iruka (富愚射華?) (referenced-only)
- Uzuki (雨月?) (referenced-only)
- Iris (
No new abilities were introduced in this chapter.
No new locations were introduced this chapter.
- The amount of money that Hikoichi was about to give to "BLAU" is 1 million yen, according to Railgun manga editor Ogino.
- The large bald delinquent that appears in the Toaru Majutsu no Index anime and manga chasing Kamijou Touma in the beginning of the series and the one that appears in the Toaru Kagaku no Railgun Manga Chapter 006 appears in this chapter as one of the people Aogami is talking to.
- The "2D, or not 2D that is the question" shown in Ruiko's examples of things one can learn from Indian Poker is an obvious reference to the famous phrase "To be, or not to be" from William Shakespeare's play Hamlet, where the title character recites a soliloquy on life and suffering beginning with the phrase.
- Sleep-learning is referenced in this chapter.
- Blau is the German and Catalan word for the color blue.
- What is the urban legend that Saten is talking about?
- Who are the administrators of that app, and how are they able to predict the place where an accident is about to happen?
- Why does Misaki want her clique to stop using Indian Poker?
- Aogami Pierce: "Even the Level 5s are laid bare before me. Literally."―regarding his erotic dreams with the two Level 5s of Tokiwadai.
- Hokaze Junko: "Oh, no. Together these two can easily pull off the perfect crime."―regarding Mikoto and Misaki.