Super Junior's Kim Heechul has apologized after criticizing an official Liberation Day banner installed by Incheon Metropolitan City to mark the 81st anniversary of National Liberation Day, which was removed due to concerns over a potential misinterpretation of the Taegeukgi illustration.

The banner was installed on August 6 near a crosswalk by the rear entrance of Incheon City Hall. It featured the phrase "The 81st Anniversary of Liberation, the Day We Regained Light" along with an illustration of an independence activist waving a Taegeukgi with both hands. However, online critics pointed out that the taegeuk pattern and the trigrams appeared to be upside down, and some users took issue with the top of the Taegeukgi being depicted in blue and the bottom in red.

As the controversy grew, Incheon City removed the banner on August 8. The city explained that the Taegeukgi was not drawn incorrectly, but rather depicted from a low-angle perspective looking up at the independence activist waving the flag. They noted that the basic form of the Taegeukgi, including the positions of the four trigrams, was correct, but it was taken down because it could be misinterpreted. An Incheon City official stated, "We failed to carefully review aspects that could cause misunderstanding on a flat surface," and pledged to pay closer attention to prevent any confusion in the future.

In connection with the issue, Kim Heechul left strongly worded comments on a post criticizing the banner. He expressed his frustration, writing, "It's baffling that they got the Taegeukgi wrong when even kindergarteners know how to draw it," and "Even K-pop fans all know the Taegeukgi." He also wrote on social media, "The issue of hanging the Taegeukgi upside down is neither a left-right political statement, nor something to be praised or criticized," adding, "It's just absurd when even foreign fans all know the correct layout of the Taegeukgi."

After Incheon City's explanation came to light, Kim Heechul issued an apology on August 9 via his Instagram. He said, "It is clearly my fault, stemming from a lack of spatial awareness and haste. I am sorry," and explained, "I failed to properly recognize the form of the flag being held by a person and lost my temper just looking at the taegeuk pattern." He continued, "Lately, I have been frequently seeing people, videos, and photos hanging or drawing the Taegeukgi upside down, so I think a lot of anger had built up inside me." He added, "It is my fault for not looking more closely at the image, and since it is only right to apologize when you are wrong, please scold me for my lack of caution." Kim Heechul also remarked, "I hope that going forward, the Taegeugki will not be distorted by other meanings or misunderstandings, including by myself," and added, "And yes, I am Korean. I was born in Hoengseong, Gangwon Province."