Taking part in the Japan Jr. youth team training camp, not as a player but as a coach in training, Mikami will ask him to submit a members chart for the regular spots out of the players who were taking part in the training camp (Captain Tsubasa arc, chapter 85, page 12). He'll submit a members chart, with which Mikami will agree on most of the members, and have a steady line in the center, but Mikami will be surprised by the suggestion of using Matsuyama as a defender (Captain Tsubasa arc, chapter 85, pages 28-29), and it will be proven to be a good idea during the match against Hamburg Jr. Youth, Japan Jr. youth not taking any goal after he's taking a position of defender (Captain Tsubasa arc, chapter 88, page 14). With Tsubasa playing as a midfielder, All Japan jr. Youth will have a steady central line with Hyuga, Tsubasa, Matsuyama as a defender and Wakashimazu, and win against Bayern Jr. Youth (Captain Tsubasa arc, chapter 89, pages 76-77), Amsterdam Jr. and Belgium Jr. Youth (Captain Tsubasa arc, chapter 89, page 82). Mikami will thank him for the idea of using Matsuyama as a defender which had proven successful (Captain Tsubasa arc, chapter 89, page 85).

While working late on All Japan Jr. youth's team formation, he'll notice Matsuyama, Hyuga and Tsubasa training late at night and will reveal it to everyone (Captain Tsubasa arc, chapter 88, pages 59 to 64). Eventually, everyone will train additionaly to improve (Captain Tsubasa arc, chapter 89, page 54).

At first Tsubasa will be unable to play because of his injury, and will understand his frustration of not being able to do something like him (Captain Tsubasa arc, chapter 85, pages 66-67). But he'll also tell Tsubasa that he isn't doing nothing from the bench, he's analysing and comparing everyone's play, and didn't give up the idea of wearing Japan Jr. youth's uniform (Captain Tsubasa arc, chapter 88, page 10). As a result, he'll be happy to hear from Mikami that he is registered as a player for the International Jr. youth tournament (Captain Tsubasa arc, chapter 89, pages 85-86), and will be introduced as a player just before the first match (Captain Tsubasa arc, chapter 90, pages 60-61). He'll get in near the second half of the match against Argentina Jr. Youth (Captain Tsubasa arc, chapter 95, pages 4-5), and score the reversal goal (Captain Tsubasa arc, chapter 95, pages 20-21), which will end up being the victorious goal (Captain Tsubasa arc, chapter 95, page 38). He'll also get in during the match against France Jr. Youth to replace an injured Izawa (Captain Tsubasa arc, chapter 99, pages 134 to 136), managing to defend at a critical moment, and toughening the defense thanks to the offside trap (Captain Tsubasa arc, chapter 99, pages 141 to 143). However, having to play extra time and unable to be replaced because the 3 substitutions were used, he'll have to play for longer than usual and eventually feel pain in his heart after a forcible breakthrough from Napoleon, but will still show determination to keep on defending (Captain Tsubasa arc, chapter 100, pages 64 to 67). He will know, however, that this match will be his last in this tournament (Captain Tsubasa arc, chapter 100, pages 76-77),

and contribute by defending (Captain Tsubasa arc, chapter 100, pages 78-79), even helping Wakashimazu to prevent Pierre from scoring (Captain Tsubasa arc, chapter 101, pages 18-19), and will be able to hold on until the end of extra time (Captain Tsubasa arc, chapter 101, pages 38-39). He'll also contribute during the PK shootout, determined to score as his last mission in this tournament, he'll score with a beautiful and magnificent penalty, convinced that his heart got stronger (Captain Tsubasa arc, chapter 102, pages 11 to 14). During the finals against West Germany Jr. youth he'll mostly support the defenders (Captain Tsubasa arc, chapter 106, page 7), and give them tactical advices (Captain Tsubasa arc, chapter 106, pages 10-11). He'll be praised at the award ceremony for his successfull penalty kick during the penalty shootout against France Jr. Youth (Captain Tsubasa arc, chapter 108, page 95).

He won't give up on being a soccer player, and like Socrates, will want to become a doctor as well as a soccer player, and so will take the examinations ot the medical school attached to the Musashi senior High school (Captain Tsubasa arc, chapter 111, page 8). He'll succeed his exams and will also have the ambition to help people who can't practice a sport when they want to (Captain Tsubasa arc, chapter 85, page 104).