RB Omiya Ardija is a football club from Saitama, Saitama Prefecture, Japan, participating in the J2/J3 100 Year Vision League. The club's full name is RB Omiya Ardija, with "Ardija" meaning "hard worker" in Spanish. They play at the NACK5 Stadium Omiya. Founded in 1964 as NTT Kanto SC, the club turned professional in 1997 and was known for many years as Omiya Ardija. A significant rebranding occurred with the investment from Red Bull, adding the "RB" prefix. The club's history includes a long tenure in J1, with their peak era being a consistent presence in the top flight throughout the 2000s and early 2010s, known for their defensive solidity. Their best J1 finish was 4th place in 2007. The modern era has been challenging, with relegation to J2 and then further to J3, leading to their current status in the Vision League as they restructure under new ownership. The fan base has a mixed reaction to the rebrand but maintains a core of loyal supporters. RB Omiya Ardija is a club with a proud top-flight history now navigating a period of transition and rebuilding.