South Korea participated in a Japanese fleet review for the first time in seven years over the weekend, the latest step forward in mending ties between the two U.S. allies. But the opposition party’s strong anti-Japanese reaction underlined that the relationship remains on shaky ground. 

The key source of the controversy domestically stems from the fact that the Japanese Maritime Self-Defense Force (MSDF) flies a flag similar to the Rising Sun, seen by many as a symbol of Japan’s imperialist past.