BUNDANG, South Korea — When Lee Kyung Eon and her friend recently scrapped plans to go to Japan for summer vacation, they paid a $135 penalty for canceling their plane tickets, joining a growing campaign in South Korea to boycott Japanese goods and services.

“We intended to do something that doesn’t help Japan, even (it’s only) a little thing,” said Lee, a 26-year-old office worker in Bundang city, near Seoul. “Many people told us we did something really good.”

A widespread anti-Japan boycott has gained ground in South Korea since Tokyo on July 1 tightened control of exports of three chemicals used to manufacture semiconductors and display screens — key export items for South Korea.

Japan’s Cabinet on Friday approved the removal of South Korea from a list of countries with preferential trade status, prompting retaliation from Seoul where a senior official summoned the Japanese ambassador and told him that South Koreans may no longer consider Japan a friendly nation.

Waving banners and signs and chanting anti-Japan slogans, thousands of South Koreans marched in Seoul on Saturday to express their anger at Japan’s decision. Huge crowds swarmed the streets in front of the Japanese Embassy, carrying signs that read “Boycott Japan” and “No Abe,” referring to Japanese Prime Minister Shinzo Abe. They shouted “We condemn the Abe government” and “Let’s end humiliating South Korea-Japan relations.”

South Korea accuses Japan of retaliating over local court rulings last year that ordered two Japanese companies to pay compensation to former Korean employees for forced labor during Tokyo’s 1910-45 colonization of the Korean Peninsula. Japan has denied that, saying its action was taken out of national security concerns.

Some question whether the boycott, mostly targeting consumer goods, can really hurt the Japanese economy as a majority of Japanese imports are parts and materials used in TVs, smartphones, semiconductors and other electronic products that South Korea exports. They worry the boycott could only aggravate the animosities as it may trigger a backlash from Japan.

But others say the campaign exposes the bitter resentments many South Koreans still harbor against their former colonial ruler. A recent survey suggested 80% of South Koreans are reluctant to buy Japanese products.

Angry South Koreans have taken to Instagram and other social media, posting videos on their canceled Japan-bound plane tickets, sharing information on which Japanese companies operate in South Korea and expressing their support for the boycott.

At hypermarkets and 24-hour convenience stores, sales of Japanese beer have nose-dived. Beer is the most popular among Japanese products. For example, at E-mart, the largest retailer in South Korea, the sales of Japanese beer from July 1-24 declined by about 38% from the previous month. Tens of thousands of small supermarkets and convenience stores across South Korea have stopped selling Japanese beer and other products altogether.

Customs officials said the imports of Japanese cars from July 1-20 was estimated at about $46 million — a 32% decrease from the same period last year. Fast Retailing Co., which operates Uniqlo, was forced to apologize recently after inviting criticism in South Korea over the remarks by one of its executives that the boycott won’t last long.

“Even without Japanese products, there are still lots of things to sell, and customers aren’t actually looking for Japanese products,” said Dan Kil-su, owner of Seoul’s Heemang supermarket who removed all Japanese products from shelves on July 5.

One of the store’s regulars, Chon Jong Lee, supported Dan’s action. “I think I originally had stronger anti-Japanese sentiments than other people. I have really bad feelings about them,” Chon said.

Past anti-Japanese boycotts didn’t last long, but some say Japan’s expected new exports limits could amplify the crisis.

“The boycott isn’t helpful in resolving the conflict, though some may feel cool by venting their anger at (Japanese companies),” said analyst Lee Sangho at the Seoul-based private Korea Economic Research Institute. “If public sentiments (in both countries) get worse, we may see a situation that spirals out of control.”

Lee Myon-woo at the private Sejong Institute near Seoul said the boycott likely will have a limited effect on the Japanese economy.

Some worry the boycott will eventually undermine the South Korean economy because a withdrawal of Japanese companies would lead to their South Korean employees losing their jobs, while fewer tourists would incur losses for South Korean tour agencies.

Ahn Kyung-su, a researcher in Seoul who planned to visit Tokyo recently for his summer vacation, called the boycott “anachronistic” and illogical. “Our TV stations mostly use Japanese-made cameras. So do we have to stop watching their programs?” Ahn asked.

Japan hasn’t yet reported a similar eruption of anti-South Korean sentiments. K-pop superstars BTS’ four concerts in Japan last month reportedly drew a total of 210,000 spectators.

At Shin-Okubo, a major Korea Town in downtown Tokyo, business was as usual last week, with many Japanese looking for K-pop music, Korean food, cosmetics and other merchandise.

Misaki Toguchi, a 14-year-old student from Saitama, north of Tokyo, said her devotion to BTS and K-pop is unshakable despite the news of the disputes. “There is absolutely no change; I still really like Korea,” Toguchi said.

The two countries are closely linked culturally. Many South Koreans like dining at Japanese restaurants, watching Japanese animation films and traveling to small towns in Japan.

Speaking before a large placard hung at his Heemang store that partly reads “We are not selling Japanese products,” Dan said his family canceled plans to go to Mount Fuji this summer. “In fact, Japan has been a country that I’ve wanted to visit,” he said.

Lee Kyung Eon, who decided to go to Taiwan with her friend this month instead of Japan, said she also used to enjoy Asahi beer, sushi, soba and other Japanese foods.

She admitted there have been ups and downs in her feelings toward Japan.

“The level of my hatred against Japan is now at one of the worst points in my life,” Lee said.