TOKYO - Japan and South Korea, whose ties have long blown hot and cold, stressed the need on Tuesday (Dec 19) to "properly manage" their differences in favour of building future-oriented ties.

Visiting South Korean Foreign Minister Kang Kyung Wha and her Japanese counterpart Taro Kono met for three hours in Tokyo, during which there was a frank exchange of views over history and the common threat of North Korea.

Dr Kang also paid a courtesy call on Japanese Prime Minister Shinzo Abe for about 20 minutes on Tuesday evening, during which they reaffirmed the joint stance of maintaining pressure to make Pyongyang give up its ballistic missile and nuclear development programmes.

Mr Kono told reporters that there was agreement on the need to urge China to play a larger role to ramp up pressure on North Korea, even if Beijing insists it has been doing its part in fulfilling United Nations Security Council resolutions.

The top diplomats of the two nations, which are both allies of the United States, met weeks after Pyongyang test-fired an inter-continental ballistic missile on Nov 29 that it claims is capable of striking the US mainland.

But even as the world tightens the noose around North Korea, a Reuters report on Tuesday suggested that Pyongyang has been able to rake in millions of dollars in virtual currencies such as bitcoin by launching global cyberattacks.

While Japan and South Korea are on the same page when it comes to their strategy against North Korea, history remains a sore point decades after Japan's occupation of Korea from 1910 to 1945.

Seoul has launched a five-month probe into the bilateral "final and irreversible" deal for comfort women - referring to those who had been forced to work in military brothels during the war - that was struck on Dec 28, 2015 under the Park Geun Hye administration.

The taskforce is set to reveal its findings on the eve of the pact's anniversary next week, South Korean media reports said. President Moon Jae In will then decide whether to retain, modify, or scrap the deal.

Under the pact, Tokyo offered an apology and one billion yen (S$11.2 million) for a foundation to be set up for those comfort women who are still alive.

Even so, comfort women statues have been erected in Seoul and around the world in honour of these women, much to the chagrin of Tokyo.

A monument erected outside the Japanese consulate in southern Busan city led to a three-month diplomatic spat during which Tokyo recalled its ambassador to South Korea.

Mr Abe and Mr Kono on Tuesday separately pressed Dr Kang to ensure that South Korea fulfills its end of the bargain regarding the 2015 agreement. Dr Kang, on the other hand, merely gave an update on the ongoing probe.

The two foreign ministers also discussed the swirling controversy over the Hashima Island, dubbed "Battleship Island".

Japan reportedly intends to state, at a new information centre on its Unesco World Heritage Sites, that Korean labourers on the coal-rich island "supported" Japan's industrial growth. The move means it avoids using the phrase "forced labour", which South Korea insists was the case.

The formerly coal-rich island off Nagasaki was this year the subject of a South Korean box office hit titled The Battleship Island - starring A-lister Song Joong Ki - that was slammed by right-wing Japanese media as distorting historical truths.

While Tokyo has said in its Unesco submission that the labourers were "forced to work under harsh conditions", it later stressed that this did not mean they were "forced labour".

Looking ahead, the two foreign ministers on Tuesday sought to pave the way for reciprocal visits by their leaders in 2018 - including the possibility of Mr Abe visiting South Korea for the Pyeongchang Olympic Games in February.

Mr Moon is, meanwhile, scheduled to visit Tokyo for a long-postponed trilateral summit meeting involving also China that is being planned for early next year.

Dr Kang returns to Seoul on Wednesday morning.