After having laid a wreath at the Darwin Cenotaph, Japan's Prime Minister Shinzo Abe has remembered the crew of a Japanese submarine sunk off the city in 1942.
A day after Japanese Prime Minister Shinzo Abe laid a wreath to honour Australians killed in the wartime bombing of Darwin he has done the same for his own countryman killed in the Top End.
A month before their air force planes bombed Darwin in February 1942, four Japanese submarines tried to attack the city but Australian defence forces sunk one of them.
All 80 seamen were killed and entombed in the I-124 submarine that now lies at the bottom of the Timor Sea off Darwin.
Mr Abe visited a memorial to the dead sailors on the sea where they died, 15km north of Darwin's CBD, and laid a wreath with Northern Territory Chief Minister Michael Gunner.
Australian Navy veteran and military historian Tom Lewis, who served in Iraq, presented Mr Abe with a couple of books he has written about the Japanese attacks on Darwin.
He told Mr Abe how much his visit will have meant to a Japanese woman he has met through his research, Atsuko Kishigami, whose father, Lieutenant Commander Koichi Kishigami, was captain of the I-124.
"He's still inside (the submarine) and he never came home," he told AAP.
"She will be really pleased that her prime minister put a wreath on the memorial ... it is a veneration of her dad's memories and deeds.
"For me, being a navy guy, it is lonely that they are there underwater."
For a long time, many Australians didn't know much about Japan's planes attacking Darwin let alone the fact they tried and failed to knock out the city's strategically important port a month earlier with submarines.
The events are also not widely known in Japan.
Darwin-based Japanese Australian woman Atsuko Kishigami became emotional when meeting Mr Abe, as she was involved with Mr Lewis in organising the memorial and hosted relatives of the dead submariners who visited the site in 2016.
She described an emotional scene in which they collected sand from Darwin's Casuarina beach to bring back to Japan as it was the final resting place of family members.
"I spoke to family descendants before this morning and they were so, so happy this was going to happen," she said.
The attack by air the next month was successful resulting in the deaths of about 240 people.
Darwin was poorly defended despite its strategic importance and Japan having signalled its intentions.
Mr Abe's visit was the first by a Japanese prime minister to Darwin and included talks with Australian Prime Minister Scott Morrison on trade and security.