BECK - Mongolian Chop Squad Wiki
Yukio "Koyuki" Tanaka
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Voiced by

Daisuke Namikawa (Japanese)
Greg Ayres (English)
Sam Concepcion (Tagalog)


14 (Birthday : December 7 - Sagittarius)


Maho Minami [Girlfriend]

Manga Debut

Guitarist, vocalist

Yukio Tanaka, commonly referred to as "Koyuki" (Tanaka's nickname given to him by childhood friend, Izumi), is the main protagonist of the series. Every day was a life of a complete nobody for the 14 year old, eighth grade student Koyuki. At the start of series being ignored by most people and spending most of his time at the arcade is commonplace for Yukio, as he has no particular hobbies or distinguishing personality traits and a rather weak taste in music. Initially, his favorite music was Okinawan pop music, in particular, an up and coming idol singer. However, his life is forever changed when he meets Ryusuke Minami, a rock 'n' roll guitarist, who just came back to Japan from America along with his dog, Beck.


Throughout the series, Koyuki is seen playing a knock off version of the GibsonGibson Les Paul & Gibson L48 Acoustic, a Gretsch White Falcon, a Fender Telecaster, a Fender Mustang​, and a Company Martin D-45.


In an early flashback, it is shown that Yukio and Izumi met in a calligraphy class when they were kids and how she gave him his nickname of "Koyuki", due to there being another "Yukio Tanaka" in the class who was much bigger than him. ("Ko" = "Little"/"Child")


Koyuki is initially a very shy, unconfident person. He thought of himself as very boring and untalented. However, he always made sure to stick up for his friends or what he thought was important. Throughout the series, Koyuki slowly developes into a more confident person. He is able to take charge and serve as an inspiration to his fellow band members.


  • Ryusuke: Yukio respects Ryusuke as the leader of "BECK" and as a friend.Though their friendly interaction is initially halted when Koyuki accidentally breaks the acoustic guitar that he lends him, Ryusuke forgives him after learning that the guitar was a knock-off he bought in New York. Over the course of the series, Ryusuke introduces Yukio to various forms of music (such 'The Dying Breed') which later on influence Yukio's playing style and taste in music.
  • Taira: Although Taira was uneasy of Yukio in the beginning, he and Yukio quickly become friends.Though they don't interact much in the series, Taira grows to respect Yukio as a musician and friend.
  • Chiba: Chiba was also uneasy of Yukio in the beginning, but they eventually become friends as the series progesses. Chiba defends Yukio on occasions due to Yukio rarely sticking up for himself. Chiba often messes with Yukio in a playful manner (such as messing up his hair whenever he styles it or unexpectedly challenging him to a wrestling match).
  • Saku: Saku quickly becomes Yukio's best friend in the series after hearing him play a Dying Breed song on the school radio one morning. They are always hanging out together in school and probably have the closest relationship. Koyuki was very sad when he learned Saku was temporarily moving away because he had found a real close friendship and connection with Saku that he hadn't really had with anyone his age before, as in middle school he was kind of a loner. They both are interested in rock bands and bond over this.
  • Maho: Maho becomes Yukio's love interest. Though their interaction at first was rough, Maho slowly opens up to Koyuki the more time they spend together. They began dating after BECK's performance at GRATEFUL SOUNDS. She was his first kiss.
  • Izumi: Izumi is Koyuki's childhood friend. She was Koyuki's first love interest.
  • Mr. Saitou: Mr. Saitou is Koyuki's mentor in swimming and guitar playing. Koyuki also works for him at his paper company and often does favors for him, like looking after his bird and throwing away his porn magazines. Since Mr. Saitou has a brash personality and low filter Koyuki sometimes is annoyed/taken aback by him but in general they have an affectionate relationship and both look out for each other and support each other's relationships and ventures. Koyuki's dad is shown to be dead so it could be interpreted that Saitou is sort of an affectionate father figure to Koyuki.
  • Momoko: Momoko is Koyuki's music teacher. Koyuki seems to be attracted to her.


Manga Plot[]

The story opens as Koyuki thinks about how boring his life is. After school, he and his friend, Tanabe, get caught spying on a former childhood friend of Koyuki's, Izumi. Later, on his way home, Koyuki saves a strange dog named Beck from some bullying kids. The dog's owner, Ryusuke, introduces himself to Koyuki and thanks him.

The next day at school, Izumi asks Koyuki to come hang out with her friends. Koyuki agrees and tags along with Izumi and her friends. Eventually, they come to a bar and Koyuki spots Ryusuke in a back corner, breaking up with a girl. When Koyuki and his friends leave the bar, they find a vandalized car and stop to look at it. The owners of the car come out of the bar, drunk. They start accusing them of vandalizing their car. Koyuki jumps in front of Izumi to defend her. Ryusuke comes to their rescue, since he can speak English and the owners of the car are American. Koyuki and his friends stop at a restaurant, but Koyuki can't eat because he's worried about Ryusuke. Koyuki leaves the restaurant and goes to find Ryusuke. Koyuki finds Ryusuke in a trash heap and is moved by what he did for him. He and Izumi go to Ryusuke's house. Koyuki feels slightly left out when Izumi and Ryusuke start talking. Later Koyuki and Izumi go to Ryusuke's band play. When they arrrive at the studio, they find Ryusuke and Eiji are fighting. Not wanting to get in the way, he and Izumi go to watch other artists preform. He watches Maho preform while they wait. After Ryusuke's band performs, he joins the band for the after party and while he's there he bumps into Maho. She asks him where the women's bathroom is, since she's not very good at reading Japanese. He remarks that she can't read Japanese like Ryusuke and she becomes offended and storms off before he can apologize.Tanabe steals Izumi's swimsuit. He shows Koyuki the stolen swimsuit and Koyuki tells him that he is done for. Tanabe begs Koyuki to help him return the swimsuit. Although reluctant to get involved and having tried to convince Tanabe to confess to Izumi what he's done, Koyuki finally agrees to assist Tanabe to return the swimsuit secretly. Koyuki and Tanabe are caught sneaking into the girls' locker room. Koyuki confesses to protect Tanabe, then freaks out and denies involvement. When told that they would be taken to the faculty room, Tanabe tells the captain that this was all just an act and that they were doing this to get attention so that they could join the swim team. Izumi quickly agrees with the lie and says it was all her idea. Izumi whispers to Koyuki that he will have to tell her the truth later. Later on, Tanabe tells Koyuki he thinks that Izumi likes him. Koyuki listens to Dying Breed's cd. He then decides to go visit Ryusuke and learn more about Dying Breed. On his way, he sees Eiji and Ryusuke having an argument.Ryusuke spots Koyuki and takes him along to a live show. Ryusuke tells Koyuki to pay special attention to the bassist, Taira. After the show, they meet up with Ryusuke's sister, Maho. She is in the middle of an argument with two men, who she succeeds in scaring off. Maho recognizes Koyuki from their previous encounter. Ryusuke leaves Koyuki and Maho to get something to eat together. Maho invites several of her friends and Koyuki soon feels very left-out and awkward. Koyuki leaves, feeling let down. When Koyuki reaches the subway station, Maho catches up with him. She takes him with her to see Beck. While visiting Beck, Maho sings part of a Dying Breed song. Koyuki thinks she is a great singer. Maho tells him that she'd like to be an actress instead. Koyuki then tries his hand at singing the song. Maho is amazed by his talent. Izumi asks Koyuki if he is going to join the swim team and invites him to meet her at the city pool later that day. Koyuki and Mr. Saitou meet, which we find out is according to Izumi's plan. Koyuki challenges Mr. Saitou to a race, with the condition that if Koyuki wins, Mr. Saitou will be his swim instructor. Mr. Saitou is easily winning when Izumi swims by and distracts him, allowing Koyuki to win. After swimming, Koyuki and Izumi head off to go see Ryusuke. When they reach Ryusuke's home, they find him practicing baseball. Ryusuke tells them that he is practicing for a Sunday baseball game. Ryusuke gives Koyuki an old guitar of his to practice on. Ryusuke plays a tune on the guitar to show Koyuki that it sounds good. Koyuki is impressed by his playing. On Sunday, Ryusuke, Koyuki, and Izumi arrive late to the baseball game. When Manabu hits Chiba with a baseball, a fight breaks out between both teams. Koyuki shouts over the crowd trying to get the fight to stop. Although the fighting stops, Chiba attacks Koyuki. Later on, at a restaurant, Maho suggests that Koyuki should be the singer for Ryusuke's band. Izumi quickly supports Maho's suggestion. Koyuki is shocked, but Ryusuke is willing to audition both Koyuki and Chiba. Koyuki tries to start practicing with the guitar that Ryusuke gave him, but he can't figure it out. His mother gives him a letter from his cousin, Hiro. In the letter, Hiro brags about his piano playing skills. Koyuki, annoyed by the letter, writes a letter about what an amazing guitarist he is. Then he hurries out of his home with his guitar to take a picture in front of the gymnasium to send along with the letter. While crossing a bridge, Koyuki trips and drops the guitar over the side and onto the road, causing the guitar to get smashed. Koyuki decides he must apologize to Ryusuke. Ryusuke invites Koyuki in and wants to have Koyuki practice singing, but Koyuki interrupts him to confess that he broke his guitar. When Ryusuke hears this, he tells Koyuki to leave and never come back. Later on, Koyuki bumps into Mr. Saitou. Koyuki has Ryusuke's broken guitar with him. Mr. Saitou asks Koyuki if he plays guitar. Koyuki explains that the guitar is broken and Mr. Saitou takes a look at it. He tells Koyuki that the guitar can be fixed and offers to teach Koyuki to play guitar.Koyuki is learning to play guitar with Mr. Saitou. Mr. Saitou lends Koyuki a guitar so that he can practice on his own as well. Mr. Saitou introduces Koyuki to his pet cockatiel, Page. Page sings along to the Beatles and any other music he likes. Mr. Saitou has never been able to make Page sing along with him when he plays. Mr. Saitou tells Koyuki he has to get good enough at playing guitar to make Page sing. Koyuki continues practicing playing the guitar. Mr. Saitou tells Koyuki that he and his old band mates are entering a music competition and have signed Koyuki up as one of the band members. Koyuki begins practicing with Mr. Saitou's band. Koyuki also continues his swimming lessons with Mr. Saitou. Koyuki receives another letter from his cousin, Hiro, this time bragging about his music instructor. Koyuki replies with a letter about his instructor and decides once and for all not to give up learning to play guitar. There is a storm the night of the music competition and Koyuki assumes it has been cancelled. While he's thinking this, Maho throws a stone through his window and asks to be let in. Maho takes a shower, since she'd been caught in the rain, then goes with Koyuki to the festival where the music competition will be held. One of Mr. Saitou's band members gets drunk and hurts himself, becoming unable to perform. Maho offers to sing in his stead. While Koyuki is in the bathroom, he overhears that the contest is rigged. He tells Maho, but she insists that they try anyway. Mr. Saitou tells them to make it a wager and whoever loses has to strip naked. Koyuki is extremely nervous about the performance, which causes him to trip as he gets on the stage. Maho asks Koyuki to accompany her in singing the song. They lose the performance, due to the men in the bathroom being correct about the contest being rigged. Koyuki and Maho sneak to the school pool after the performance and Maho strips down and swims naked, since she lost the wager. Koyuki is nervous about being caught until Maho starts singing Dying Breed's song, "Swimming Bare". Koyuki then takes off his clothes and joins her in the pool. They sing the song together until a drunk Mr. Saitou interrupts them, telling them that he beat up the winners and took their prize.


  • In the Filipino Dub of the anime series, he is voiced by ABS-CBN Kapamilya actor and singer, Sam Concepcion, before he went a four year hiatus and returned as a recording artist.


  • Gretsh White Falcon
  • Fender Telecaster
  • SG
  • Fender Mustang


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