The J. League said Monday it has issued a ¥1 million ($9,100) fine to second-division team Kyoto Sanga after a club supporter waved a flag with a design that evokes Nazi Germany during a preseason match in February.
The supporter waved the flag in question at a match between Kyoto and first-division opponents Cerezo Osaka at Sanga Stadium. The fan had hoisted the flag at almost every home game since 2010 but did not know what the design signified, according to a league statement.
While Kyoto had checked whether banners brought to the stadiums by fans were appropriate, they had not confirmed the designs of individual flags, the J. League said.
"We will work together with fans to take preventative measures and create a stadium that everyone can enjoy," club chairman Masaaki Ito said in a comment.
The team also apologized in a statement issued in February after the incident came to light.
The J. League has taken a harder stance against inappropriate displays and racist conduct since 2014, when a banner reading "Japanese Only" was displayed inside the Saitama Stadium concourse during a J1 game between Urawa Reds and Sagan Tosu.
That incident led to Urawa being sanctioned with the league's first closed-door game by chairman Mitsuru Murai, who had taken his post just weeks earlier.
In 2017, members of a supporter group backing Gamba Osaka were handed an indefinite stadium ban after they were found to have waved a flag resembling the "SS" logo of the Schutzstaffel, the Nazi paramilitary force.