Soma was born in Shizuoka on July 19, 1971. After graduating from Waseda University, he joined Kashima Antlers in 1994. He played as left side-back and became one of the main player in glorious era of the club. In 1990s, the club won the champions in 1996, 1998 J1 League, 1997 J.League Cup and 1997 Emperor's Cup. He was also selected Best Eleven for 4 years in a row (1995-1998). In 2000, the club won all three major title in Japan; J1 League, J.League Cup and Emperor's Cup. However at Emperor's Cup in December 2000, he got hurt and he could not play about a year. Although he came back in the latter half of 2001, his opportunity to play decreased behind Augusto. In 2002, he moved to Tokyo Verdy on loan. He returned to Kashima Antlers in 2003 and moved to Kawasaki Frontale in 2004. At Kawasaki Frontale, he played as defensive midfielder and sweeper. He retired end of 2005 season.
National team career
On May 28, 1995, Soma debuted for Japan national team against Ecuador. After debut, he became a regular player as left side-back and left midfielder. In 1996, he played in all matches included 1996 Asian Cup. At 1998 World Cup qualification in 1997, Japan won the qualify for 1998 World Cup first time Japan's history. He played in all matches at 1998 World Cup. He also played at 1999 Copa America. He played 58 games and scored 4 goals for Japan until 1999.[1]
Coaching career
Soma retired at the end of the 2005 season. After working as a TV pundit, Soma managed the Japan Football League side FC Machida Zelvia in 2010. He held a managerial post in charge of J1 League side Kawasaki Frontale prior to the 2011 season. On April 12, 2012, Kawasaki dismiss coach Naoki Soma after performing 'far below expectations'. The 40-year-old coach was sacked with the club's president stating the team were performing 'far below expectations' having aimed to win the title this term. In 2014, he signed with J3 League side FC Machida Zelvia again. He led the club to won the 2nd place in 2015 and promoted to J2 League.
