Masaki Oyokawa

He started playing little league baseball in 3rd grade for Suka Elementary, and was chosen to play for the Chiba Lotte Marines Junior team in his 6th year.^[3] He continued playing baseball for Yokaichiba Daini Junior High, and was selected to pitch for the national team in the 2016 WBSC U-15 Baseball World Cup.^[4] He helped Japan finish 2nd overall, and he earned the lowest ERA pitcher award as well as a "Super Junior High pitcher" reputation for his 140 km/h fastball.^[5]

He entered Yokohama High School, a known baseball powerhouse in Kanagawa prefecture, and became the team's ace in his 2nd year.^[6] But despite his team making it to national tournaments for 3 years in a row, he failed to pitch well in several games that at one point he was stripped of the ace jersey (#1).^[7] In his final year, his team almost made it to the summer prefectural finals but lost to the opponent when he gave up 3 runs in less than 2 innings of relief. This was the first time his school was defeated by a public high school in the prefectural tournaments, last occurred in 1997 when Daisuke Matsuzaka was a sophomore pitcher there.^[3] Nevertheless, his 153 km/h (95 mph) fastball was enough to gain scout attention and he was one of the top high school prospects of the 2019 draft, along with Junya Nishi, Rōki Sasaki and Yasunobu Okugawa.^[8]