I was discussing Shuukichi in another thread but the topic sort of changed to the popularity of Shuuichi and Rei so I'm going to move my questions about Shuukichi over here. For anyone wasn't apart of that conversation, I was questioning how Shuukichi could be the middle brother based on what we know about both characters. The questions will be below the massive wall of text.
So far the things we know about Haneda Shuukichi are as follows: "10 years ago" (age 18) he was playing at a tournament level. He won the match because his opponent made 2 moves in a row by mistake. After leaving that match he boards a train and falls asleep. Here he meets Yumi who wakes him up to make sure he gets off at the right stop. He realizes that she went out of her way for him and eventually they begin dating. "Several years ago" Yumi and Shuukichi are meeting somewhere after he wins the Mejin title (the first time) and Yumi mentions a Sumo wrestler who has won six title matches in the span of one year, this motivates Shuukichi to win all seven Shogi titles to gain more love from Yumi and make her feel like a queen. A Christmas some time after that he gives her an envelope with something special in it that he tells her not to open until he collects seven special things. After this Yumi dumps Shuukichi for the sake of her job as a traffic cop. In the current time line we have the "Ex-Boyfriend next door" case (His current age is 28 and he is living at Beika Chateau Condos). From this case we, the reader/viewer, learn of his ability to memorize things like the code to the lock box with the spare key, and the contents of the suicide note from the crime scene. We also learn that Shuukichi has at least some form of decent fame as several people seem to recognize him even if they didn't immediately know who he was (Megure and Takagi). We also learn of the concept of "a well prepared move" and that it is Shogi terminology. At the end of the case we find out that Yumi does not know what a "Mejin" is and does not know that Shuukichi plays Shogi. In the more recent Shogi case, "2 days ago" Shuukichi and Yumi meet at a restaurant because he has almost collected all seven things and Yumi says that she has thrown the envelope away without looking inside of it. As they leave the restaurant someone recognizes him to be "Taiko Mejin" despite him being in his everyday attire of wearing glasses and being unshaven. This Shogi tournament is him reclaiming of the Mejin title (the second time). Before the second part of the match he is given an envelope saying that Yumi has been kidnapped, he then races to Tokyo. While at the Meiji shrine he bumps into Conan and DB. DB mention that the Taiko in his name refers to Toyotomi Hideyoshi, but he says its just a nickname. The case does mention Hideyoshi a few more times. During the case we are made aware that the Mystery girl was watching the Shogi match on tv. However by the time Masumi enters the room, mystery girl has turned off the tv and has her eyes closed and laying down. Masumi turns on the tv and sees the match but by this time only Shuukichi's opponent was actually there on the screen. The end of the case brings a full resolution to the events of "10 years ago" at the Hotel Hyde Pride, where Masumi and Mystery Girl are currently staying. Even though Yumi hears that Shuukichi is going to a Meijin, and she sees that other people are treating him as if he is famous, she still doesn't know of his Shogi background, but rather thinks he is a Rakugo story teller (its a form of "sit-down" comedy sort of comparable to western "stand-up" comedy). At the end of the chapter we see Masumi in her coat carrying her helmet saying that she saw police cars outside. The Mystery girl is shown turning off the tv (we don't know if Masumi saw whether or not she watched the end of the match, we only know that she turned off the tv). The Mystery Girl claims to not know why there are police cars outside and smiles. Subaru (Shuuichi) is shown reading an article about Shuukichi and he smiles as well (I assume that's another cup of Bourbon next to his laptop).
So far the things we know about the Middle Brother are: The very first time that we can see for ourselves that Masumi has contacted the Middle brother is the "Adultery Case" in chapter 857. Kisaki Eri overheard Masumi in the hotel lobby several hours before the case talking on the phone to someone who she attached -nii (brother) to the name. During the case the person on the phone with Masumi tells her that there may be a problem in her deduction, however she gives it anyway. This prompts Conan to do the Shinichi cell phone routine in front of Masumi (for the fifth time, the other times were Haunted Hotel, Detective Agency Hostage Crisis, East v West Rematch, and Yusaku's Cold case). It is heavily implied that Masumi may already know that Conan is Shinichi. Eri tells them what she heard when picking them up. It should be noted that in this case Masumi talked with her brother on the phone, but after this she has only been seen texting him until the very end of the "Red Woman" case. In the next case "Suspect is Kyogoku Makoto", Conan asks her how she could be talking to her nii if she has already said that she heard that he had died. Masumi explains that she has a second-oldest brother that looks like her father rather than her mother like she and her eldest brother. She also says that he is on an important job and would't let her know his whereabouts, but that he sometimes advises her on cases over the phone. Later in the case Masumi texts her Middle Brother and he asks who Masumi keeps referring to as the person who is there with her looking for clues. This means that Masumi didn't explain it to him in the previous case. Masumi sends him a picture of Conan and he seems to think that if Conan is involved that there will be no problem, meaning that he has probably met Conan and seen his abilities, possibly even knowing his secret but that is not known. He then gives a plausible explanation on how he knows Conan and then has a PS: Have you already met the wizard? Masumi seems to think that she has and looks over at Conan. In this case we also see the Middle Brother's arm, it is light skinned and holding a black cellphone with a black long-sleeve shirt sleeve in the frame. In the "Red Woman Case" we have Masumi and the group invited to solve a mystery at a Holiday Villa, that the Middle Brother could not go to in person because he was busy. Masumi states that the Middle Brother is not a detective but often solved "mysteries and puzzles" in class in high school. During this case we also learn about the Middle Brother's high school friends and his name switches. According to Masumi the three siblings all have different family names. After the death of their father, both she and the Middle Brother had the family name "Sera". The Middle Brother then changed his family name to something else after he graduated high school. It is not mentioned if the eldest brother has changed names or not because Conan tries to ask about the original family name but they are interrupted by the Red Woman. Because the Middle Brother's high school friends are ages 28-29 it can be assumed that the Middle brother can be at least one year up or down from their ages meaning he can be 27-30 (I say this because of the ability to enter school early/late based on birthday, as well as the ability to pass/fail grade levels, and we have no way of knowing it any of this can apply to the friends or the Middle Brother himself). Interestingly enough after re-reading the chapter it seems it was never stated that they were actually classmates, just that they were all "friends". If he was well known enough from solving mysteries at the school, he would be known and possibly befriend people from other grade levels, but I'm still going to keep the 27-30 range. The friends confirm that the person they knew was indeed called "Sera-kun" during high school. Even though it seems they were told that their friend's sister was coming, they don't seem to recognize her at all and they never even mention an eldest brother. It is mentioned that during high school that the people present in the case were a part of the "outdoor club" for the summer holidays, and say that the club was just the five of them meaning that "Sera-kun" was not a part of the club (Satoko, the fifth member, was murdered 12 years ago near this same villa during a school holiday). In the previous case she had confirmation of her Middle Brother knowing Conan and that "if its him it will be ok", Masumi really has no reason to call him during this case while he is "busy". I do want to point out however that Masumi does say "They don't exist, Evil Spirits and Ghosts, Witches and Wizards, they live in fantasy worlds, not one of them exists", but then on the next page she says that she returned to Japan "to meet the Wizard again" while looking down at Conan. At the end of the case Conan says that she needs to call her Middle Brother and tell him how the case went, instead of this she sends Conan to look for her phone because she says she misplaced it. This reveals to Conan the first image of the Mystery Girl. She then calls, or pretends to call her Middle Brother to explain the case while peering at Conan. Over all the Eldest Brother is described as three times stronger than Masumi and is the one that sent her the Jeet Kune Do tapes that she watched many times as a kid. The Middle Brother is described as intelligent and one who likes to solve "mysteries and puzzles". Shuuichi, as Subaru, has demonstrated he is very intelligent and calls himself a Sherlockian. He also says he likes to solve "puzzles". If he and the Middle Brother are different people, the the Middle Brother's intelligence must be much higher than that?
Questions: If Shuukichi is the Middle Brother, then
Shuukichi was first introduced as a Shogi playing man who could memorize things very quickly, and was introduced three cases before the first mention of the Middle Brother. Why would you want to introduce a new character and then suddenly create an alternate persona for that character after the fact and not let the audience know? It would seem kind of silly to me to even make a secret Middle Brother and only introduce one person that it could be, and then it turns out that it is that person.
Shuukichi was already playing Shogi at a tournament level at a point "10 years ago", at this time Masumi would have been at least 6-7 and would most likely remember that he was such a good Shogi player. Even with Shuukichi having gone off to college and being separate from the family, he still would have graduated some time before Masumi left from japan "3 years ago". If Shuukichi was the Middle Brother, then Masumi would definitely know that he is fond of Shogi. Why did she then describe him as liking "puzzles" rather than liking "Shogi"? Why would Masumi not know his whereabouts? If she wanted to see him, she would most likely just go to Shogi tournaments and hang around. From Masumi's point of view, even if her brother was not going to tournaments anymore there is a chance he would still watch them on tv and possibly see her in the background, so it would be worth it. Why isn't she shown even attempting this? From Shuukichi's point of view, why would he want his whereabouts unknown if all he was doing is playing Shogi? Why would Shogi be a tough enough job that he couldn't take a break to see her briefly? On top of that, how do you explain that Masumi never contacted him in any of the cases that she appeared in before the Adultery case? How would she suddenly have gotten in contact with him? If she had contact with him before the first time we see her call him, why is she suddenly self-conscious enough to ask him if she is right about her deduction in the case where she calls him, but didn't call him before?
For the most part we assume that Masumi and her mother left Japan due to something involving Shuuichi while he was inside the BO. Shuuichi entered the BO "5 years ago" and they left Japan "3 years ago" and Shuuichi left the BO "2 years ago". If Masumi and her mother were evacuated from Japan due to fear of the BO, why did the Middle Brother not go with them? You can say that if he is Shuukichi that he has the reason of the Shogi titles to stay in Japan, but wouldn't life or death situations trump titles that he could earn at any time in his life? If Shuuichi still had the family name Akai, and by this time they still feared that Masumi and the mother, who have the family name Sera would still be found by the BO, why would the Middle Brother having a third family name even protect him? He allows himself to be put on tv and in internet articles. He doesn't seem like he is hiding from anyone.
Masumi's description of the Middle Brother is very vague. She says that she and her Eldest brother resemble their mother, but that the Middle Brother resembles their father, who is dead. Because we still have the potential of meeting the mother of the family, we would see the resemblance between Masumi, Shuuichi, and the mother pretty clearly. The father however is dead, and the Middle Brother looks like him more than the other three. At this point all we know about his appearance is that he does not look like his other three family members. Combining that with having a different family name, you could almost pull a random person off the street and have them fill in for the Middle Brother as long as the age is correct. On top of this, Shuukichi's current family name matches the same "Haneda" kanji as someone from the APTX victims list. Wouldn't it be far more likely that he is related to that person rather than having to be the Middle Brother and just happening to change his family name to that around the time he graduated High school?
At the end of the recent Shogi tournament case we see the Mystery Girl and Shuuichi smiling. Since the Mystery girl had the tv on the station giving coverage of the tournament earlier in the case, it is assumed that she was still watching it when she turned the tv off at the end. Shuuichi is shown definitely reading an article about the Shogi tournament and the winner of the seven titles. So many people made the immediate jump from "Oh my god, they smiled at Shuukichi's achievement" to "Oh my god, they are all blood-related/family members". We still do not know that the Mystery Girl is the mother of the family, we only know that she talks like an adult and has the same black outline of the eye that Masumi does. How do you make this big leap? Why would Gosho let a simple smile confirm the identity of two characters that are supposed to be a mystery??
Remember that the Bourbon arc started off with just the mention of Bourbon and only having Subaru as a suspect for a really long time drinking Bourbon in the Kudou house before Masumi and Amuro were actually introduced (14 volumes / 142 episodes later).