Two Japanese Cabinet ministers were among dozens of MPs who visited a war shrine in a move sure to anger China and South Korea, which see it as a potent symbol of Tokyo's imperialist past.
Hundreds of police surrounded the leafy Yasukuni shrine in the heart of Tokyo, as right-wing nationalists carried flags calling on visitors to pray for Japan's "heroic war dead" on the anniversary of the country's surrender in World War II.
Prime Minister Shinzo Abe, a conservative who is bent on reviving Japan as an economic force, was expected to stay away from the shrine, but reportedly sent a ritual offering via an aide.
Yasukuni honours 2.5 million citizens who died in World War II and other conflicts, including 14 top convicted war criminals such as General Hideki Tojo, who authorised the attack on Pearl Harbour.
Visits to the site by Japanese politicians enrage neighbouring nations, which view them as an insult and painful reminder of Tokyo's aggression in the first half of the 20th century, including a brutal 35-year occupation of the Korean Peninsula.
Yoshitaka Shindo, Internal Affairs and Communications Minister in Abe's Cabinet, visited the shrine.
About 90 other MPs arrived at the site later in the morning.
"It was my personal decision to come here," Shindo said, adding it was a "private" matter that should not affect Japan's diplomatic relations.
Another Cabinet minister, Keiji Furuya, who is in charge of the North Korean abduction issue, also made the trip.
Tokyo is pressing North Korea to return all Japanese citizens kidnapped by Pyongyang in the past - the victims were largely used to train North Korean spies.
"Consoling the souls of war dead is purely a domestic issue," Furuya told reporters. "This is not something that other countries are supposed to criticise or interfere with."
Abe gave a ritual offering earlier this year when nearly 170 MPs visited the shrine for a spring festival, grabbing international headlines and sparking diplomatic protests.
On last year's surrender anniversary, more than 50 MPs made the pilgrimage to the site near Japan's Imperial Palace, drawing protests from Seoul and Beijing.