Japanese Prime Minister Kishida Fumio, who began his first visit to South Korea since he took office, laid flowers at a national cemetery in Seoul.
The cemetery houses graves of the country's past presidents and those who died in the Korean War.
Kishida and his wife Yuko, who arrived at a military airport outside Seoul shortly before noon on Sunday, laid flowers before a monument and offered a silent prayer.
Kishida is scheduled to meet with South Korean President Yoon Suk-yeol later on Sunday.
Kishida's visit is part of what the two countries call "shuttle diplomacy" he and Yoon agreed to resume in March. The leaders intend to pay mutual visits to strengthen bilateral ties.
Kishida is the first Japanese prime minister in 12 years to visit South Korea for summit talks.
The two leaders are expected to stay in close communication in order to speed up efforts toward better ties. They also plan to agree on boosting security cooperation to address issues including North Korea's nuclear and missile development.