Ikuma Sekigawa (関川 郁万, Sekigawa Ikuma, born 13 September 2000) is a Japanese professional footballer who plays as a centre back for J1 League club Kashima Antlers.^[1]

Born in Tokyo, Sekigawa started playing football when he was three years old. He joined his first club, FC Tama Junior Youth, whilst he was in elementary school.^[2] He attended high school at Kashiwa High School attached to Ryutsu Keizai University where he played from his first year. In 2016, aged 16, Sekigawa's high school were runners-up in the Inter High School Championship following a 1–0 defeat to Funabashi Municipal High School.^[3] Sekigawa played 4 times in the competition, as well as another 8 games in the Prince Takamado Trophy JFA U-18 Football League.^[4] The following year Kashiwa High School went one better in the Inter High School Championship and were crowned champions.^[5] Sekigawa started all five games and was one of the driving forces behind the victory – drawing some comparisons to Kashima Antlers centre-back Naomichi Ueda.^[6] During the competition, Sekigawa scored a hat-trick in their third-round 5–0 win over Ichiritsu Nagano High School.^[7] They also finished runners-up in the All Japan High School Soccer Tournament, following a 1–0 defeat to Maebashi Ikuei High School. In his final year at high school, Kashiwa High School once again lost in the final of the All Japan High School Soccer Tournament – this time a 3–1 defeat to Aomori Yamada High School. The game was played in front of 54,194 supporters at Saitama Stadium 2002.^[8] Again Sekigawa was amongst the goals throughout the competition, scoring three goals in five games. In May 2018, it was announced that Sekigawa would be joining J1 League club Kashima Antlers for the 2019 season.^[9][10]

In his final competition for his high school, he was made captain for the 2018 Prince Takamado Cup,^[11] where he made 12 appearances and scored one goal.^[12]

In April 2019, Sekigawa made his professional debut for Kashima in a 0–1 AFC Champions League defeat to Gyeongnam FC.^[13] In his debut season, he played twice in the AFC Champions League and made one appearance in the Emperor's Cup.^[14]

Sekigawa made his J.League debut in the 2020 season, starting at centre-back in a 3–0 defeat by Sanfrecce Hiroshima.^[15] He went on to make 17 appearances across all competitions, playing over 1000 minutes of J1 League football and also making his first appearance in the J.League Cup.

In the 2021 season, Sekigawa scored his first goal for the club in a 2–1 defeat to Urawa Red Diamonds.^[16] Following an indirect free-kick from the opponents half, Sekigawa looped a header over the goalkeeper to draw the game level.^[17] This was his first game back following suspension after receiving his first red card in a 1–0 defeat to Avispa Fukuoka the previous month.^[18] Sekigawa made 21 appearances across all competitions.

Following the departures of defenders Tomoya Inukai and Koki Machida before the start of the 2022 season, Sekigawa was handed the number 5 shirt was afforded much more playing time.^[19] He was first-choice centre-back for much of the season.

As of 3 December 2023^[20][21]

Sekigawa has been selected for the U-16, U-17 and U-20 national team squads.^[9] However, he twice had to pull out of U-16 squad call-ups due to injury, firstly in August 2015^[22] and secondly in May 2016.^[23] In 2019, he was called-up to replace the injured Ryotaro Tsunoda as part of the U-20s Chiba training camp before the 2019 FIFA U-20 World Cup, although Sekigawa did not make the squad for the tournament.^[24]