Ayumu Seko

2.1. Growth in Youth Clubs

Seko's entry into organized football was influenced by his childhood friend, Masaki Ikeda, who joined the Cerezo Osaka junior youth program. This inspired Seko to attend the selection trials for Cerezo Osaka U-12, which he successfully passed, marking his official start within the club's prestigious youth academy in 2010. He steadily progressed through the ranks, advancing to Cerezo Osaka U-15 from 2013 to 2015 while attending Taisho Higashi Junior High School, and then to Kokoku High School from 2016 to 2018 during his time there.

In 2016, while still part of the U-18 squad, Seko was registered as a Type 2 Registered Player with the Cerezo Osaka top team. This special designation allowed him to gain invaluable professional experience by playing for the Cerezo Osaka U-23 squad in the J3 League. Competing against physically stronger, more experienced players in the J3 League significantly contributed to his development, enabling him to adapt more quickly when he eventually joined the senior J1 League team. By 2017, his talent caught the eye of then-Cerezo Osaka coach Yoon Jong-hwan, who invited Seko to participate in top-team training sessions, an unusual step for a player of his age. This accelerated progression culminated in his senior debut for the club in the J.League Cup on May 24, 2017, against Vissel Kobe. At 16 years and 11 months old, Seko became the youngest player in Cerezo Osaka's history to debut in a cup competition, showcasing his exceptional potential from an early age.

3.1. Cerezo Osaka

On October 19, 2018, Ayumu Seko officially signed his first professional contract with Cerezo Osaka, marking his full transition from the youth academy to the senior squad. His impact began to be felt significantly during the 2019 season, when he made his J1 League debut in the 10th match against Matsumoto Yamaga FC. Under the guidance of coach Miguel Ángel Lotina, Seko's build-up play, particularly his accurate low-trajectory long passes, was highly valued, leading to increased playing time. On September 1, he scored his first J1 League goal against Kawasaki Frontale. Seko's defensive contributions were crucial that season, helping Cerezo Osaka concede only 25 goals, which was the fewest in the entire J.League across all divisions that year, and the second-lowest in J.League history, setting a new club record for minimal goals conceded.

The 2020 season saw Seko firmly establish himself as a starting defender, consistently appearing in the lineup from the opening match. He formed a formidable partnership with Matej Jonjić at center-back, with his strong defensive efforts and trademark low-trajectory long passes proving highly effective. His outstanding performance in the J.League Cup, where he played in four matches, earned him the prestigious 2020 J.League Cup New Hero Award on November 2, a historic achievement as he was the first Cerezo Osaka player to receive this honor. Furthermore, after making 27 appearances in the league, he was also recognized with the Best Young Player Award for the 2020 J1 League season. This remarkable feat of winning both the J.League Cup New Hero Award and the Best Young Player Award made him only the fourth player in J.League history to achieve this double distinction, following in the footsteps of players like Yosuke Ideguchi.

In the 2021 season, Seko continued to anchor Cerezo Osaka's defense, forming a notable center-back partnership with Ryuya Nishio. This duo was particularly unique due to their young ages (20 and 19 respectively) and the fact that both were homegrown talents from the club's youth academy. Their combined strength and synergy were a testament to the club's successful youth development program. Their impressive play together earned both Seko and Nishio their first call-ups to the Japan national football team on December 7, highlighting their rising prominence in Japanese football.

3.2. Grasshopper Club Zürich

Ayumu Seko's talent drew attention from European clubs, leading to his transfer to Grasshopper Club Zürich in the Swiss Super League on January 18, 2022, a move he described as a dream come true. Upon arriving in Switzerland, Seko quickly integrated into the team, adapting to new tactical demands.

During the 2022-2023 season, his versatility was increasingly utilized, with the coaching staff often deploying him as a defensive midfielder in addition to his primary role as a center-back. This adaptation showcased his ability to contribute defensively and in build-up play from a deeper position. In the 2023-2024 season, Seko solidified his position as a regular starter, making 36 appearances in the league. While his preferred position remains center-back, he frequently played in an anchor role within a double defensive midfield due to the team's existing strong contingent of center-backs. His consistent presence and adaptability underscore his value as a key player for Grasshopper.

4.1. Youth National Teams

Seko's international journey began with selections to various Japanese youth national teams, starting from the U-15 squad. He represented Japan in the AFC U-16 Championship and the U-16 International Dream Cup in 2016. In 2017, he participated in the Vaclav Jezek International Youth Tournament with the U-17 squad. Despite being a prominent youth talent, he unfortunately missed out on selection for the FIFA U-17 World Cup due to an injury.

However, Seko's determination saw him rebound, and in May 2019, he was selected for the FIFA U-20 World Cup squad, fulfilling a long-held ambition after his earlier setback. He also continued to feature for the U-22 and U-23 teams, participating in several international friendly matches and tournaments, including the Kirin Challenge Cup. For the Tokyo Olympics held in 2021, Seko was initially called up as a backup member for the U-24 team. Following a rule change, he was promoted to the main tournament squad, although he did not make any appearances during the competition.

4.2. Senior National Team

Seko received his first call-up to the senior national team in January 2022 for a friendly against Uzbekistan. However, the match was ultimately canceled due to COVID-19 restrictions, delaying his senior international debut.

His opportunity arrived in March 2023, when he was called up by coach Hajime Moriyasu for the Kirin Challenge Cup friendlies. On March 24, 2023, Seko made his highly anticipated debut for the Japan national team, playing the entire match against Uruguay, which concluded in a 1-1 draw. He subsequently made another appearance on June 20, 2023, coming on as a substitute in the 36th minute of the second half against Peru, a match Japan won 4-1. As of November 19, 2024, Ayumu Seko has accumulated 4 international A-match caps for Japan, without scoring any goals.

7.1. Club

• Cerezo Osaka U-15
  • Prince Takamado Cup U-15 Soccer League Kansai Sunrise League: 2014
  • Prince Takamado Cup JFA All Japan U-15 Football Championship: 2015
• Cerezo Osaka
  • J.League Cup: 2017
  • Emperor's Cup: 2017
  • FUJI XEROX SUPER CUP: 2018

7.2. Individual

• Japan Club Youth Football Championship (U-15) - Tournament Excellent Player: 2015
• J.League Cup New Hero Award: 2020
• J.League Best Young Player Award: 2020