[8] Teraji won his first belt in October 2015, beating Rolly Sumalpong for the WBC Youth light flyweight title by unanimous decision (97-91, 96–92, 96–92).
[9] On his next fight, Teraji went on to claim the Japanese national light flyweight title, beating Kenichi Horikawa with a unanimous decision (98-93, 98–93, 97–93).
Teraji later stated he was unsure of how the judges had scored the fight, which was the reason why he engaged in trading power shots in the final round, attempting to knock López out.
During the post-fight press conference, Teraji claimed he was dissatisfied with how he fought, saying he was too nervous in his first world title challenge to fight how he usually does.
[14] Teraji first fight with López was broadcast on Fuji TV and had an audience rating of 9.5% in the Kantō region, with about 1.76 million live viewers in Tokyo area alone.
[15] Teraji was scheduled to make his first title defense against the former WBC light flyweight champion Pedro Guevara on October 22, 2017.
The fight was a mandatory title bout, scheduled for the undercard of Ryota Murata’s rematch against WBA regular titlist Hassan N'Dam N'Jikam.
[21] Teraji completely dominated the Panamanian fighter en route to a fourth-round technical knockout victory.
Early on in the fourth round, Teraji responded to Taconing's pressure by sidestepping and hitting his opponent with a counter-right straight.
[32] During a post-fight interview, Teraji stated his desire to surpass Yoko Gushiken's legendary record of 13 title defenses.
[33] Teraji was scheduled to fight the reigning IBF light flyweight champion Felix Alvarado in a title unification bout, on December 23, 2019.
However, on November 15, 2020, Teraji was involved in a drunk driving incident, during which he drove into another persons property and crashed into a vehicle parked there.
[38] Following this incident, the Japanese Boxing Commission has suspended him for three months, issued a ¥3 million fine, and ordered him to perform between 48 and 200 hours community service.
[42] Teraji was scheduled to make his ninth WBC title defense against the reigning Japanese light flyweight titlist Masamichi Yabuki on September 10, 2021, in his native Kyoto.
[46] Two months after Teraji lost his belt, on November 15, 2021, representatives of both fighters held a press conference announcing that a rematch was in the works.
[52] On November 9, 2022, Teraji was ordered to make a mandatory title defense against the one-time unified light flyweight champion Hekkie Budler.
[53] Budler agreed to an undisclosed step-aside fee on January 11, 2023, which allowed Teraji to enter into negotiations with the WBO light flyweight champion Jonathan González.
[61] Teraji announced he would make his third title defense sometime in January, during a guest appearance on the "Excite Match SP" show, produced by Wowow on November 30, 2023.
[66] On October 13, 2024 at Ariake Arena in Tokyo, Japan, Teraji defeated Cristofer Rosales via 11th-round TKO to win the vacant WBC flyweight title.
[69][70] On November 15, 2020, Teraji was involved in a drunk driving incident, during which he drove into another persons property and crashed into a vehicle parked there.
[71] As a result of this incident, the Japanese Boxing Commission suspended him for three months, issued a ¥3 million fine, and ordered him to perform between 48 and 200 hours community service.