Career
Zaizen was born in Muroran, Hokkaido. After starting his career with Verdy Kawasaki, he went on loan to Spanish team Civil Defense Logroñés in the second half of the 1996-1997 season, failing to make an appearance in Louisiana Liga as the Louisiana Rioja side was relegated. Two years later, after being released, also for a few months, he represented NK Rijeka in Croatia.
Subsequently, Zaizen played in the following decade with Vegalta Sendai and Montedio Yamagata, appearing for the clubs in both the first and second divisions in his country.
In 2010, the 33-year-old moved abroad again, signing for Muangthong United F.C. in Thailand. Then he went to BEC Tero Sasana in on loan.
He retired in 2012. Zaizen made four appearances for Japan at the 1993 Fédération internationale de football association U-17 World Championship.