[1][2][3] In his third year, he won the Kinshuki Cup, and also won the Inter-High team competition with classmate Iori Yamada and one year younger Kentaro Iida, achieving a triple crown in the high school team competition (All Japan High School Championships, Kinshuki Cup, and Inter-High).

[5] At the 2017 World Judo Juniors Championships, he won consecutive matches by ippon with seoi nage and sode tsurikomi goshi to advance to the finals, where he won all five matches by ippon, including defeating Robert Florentino of the Dominican Republic with a seoi nage, to win the championship.

[9] In the student weight class, he suffered a bleeding head injury in the semi-finals, but in the final he defeated Shinsuke Yokouchi, a junior at university, with a seoi-nage to win the championship.

[12] In the Kodokan Cup final, he faced JRA's Mashu Baker, a gold medalist at the 2016 Summer Olympics, and although he won first with a waza-ari, he was defeated by a combined technique and finished second.

[14] At the Judo Grand Slam Ekaterinburg in March 2019, he defeated former world champion Nemanja Majdov of Serbia by waza-ari in the second round, but lost to Georgia's Beka Gviniashvili by uranage in the quarterfinals.

[23] In the April 2022 weight class, Tajima defeated Nagasawa Kenta, a senior at the company, by seoi-nage in the semifinals, but lost to Masuyama by disqualification in the final, just like the previous year.

[33][34] In the following All Japan Championships, he won all of his matches by ippon, including a disqualification win against Chofu Kogyo's Harazawa Hisayoshi, a silver medalist in the over 100 kg class, in the quarterfinals, and advanced to the semifinals, where he won by ippon and advanced to the semifinals, where he lost by waza-ari to Asahi Kasei's Ojitani Takeshi, but still placed third in the 90 kg class.

[39] In the following Grand Slam Ulaanbaatar, he lost his first match to Mikhail Igolnikov of Russia, who was competing as a neutral athlete, by combined waza.