Forty years ago dozens of Vietnamese soldiers were killed in a bloody battle with Chinese troops over disputed islands in the South China Sea.
This year, for the first time, Vietnam's state media is publicly marking the event, printing numerous articles on the battle.
The move comes in the month that the Chinese government published new rules requiring foreign fishing vessels to seek Beijing's permission to operate in most of the South China Sea - an action likely to further raise anti-China rhetoric in the Vietnamese press.
Prior to the battle, Vietnam had controlled some islands within the Paracel archipelago (Xisha in Chinese) and China had controlled others. Both sides claimed them in full, as did Taiwan.
On 19 January 1974 a clash erupted between the South Vietnamese navy and Chinese forces.
Three of the four Vietnamese warships had to retreat while the fourth sank with its captain on board.
As a result, China gained control over the entire group of islands, now part its newly-established Sansha prefecture.
The current government renewed Vietnam's claim to the Paracels (Hoang Sa in Vietnamese) after the Vietnam war ended, but to date has rarely mentioned the 1974 naval clash. The event is not even included in modern history textbooks.
Up to 1975 the Paracel archipelago was claimed by the US-backed Saigon government. At the time Hanoi did not protest China's occupation of the islands nor - for a long time - recognise the South Vietnamese soldiers' loss of life - because they were considered by the communist North to be an enemy army.
But historian Nguyen Nha, who specialises in South China Sea issues, says things have now changed.
"We have to realise that there are no more North and South, we're all Vietnamese. Politics come and go, but historical facts remain."
This change of heart is clearly visible in Vietnamese media.
National newspapers like Thanh Nien and Tuoi Tre have in recent weeks been running a series of reports including detailed accounts by witnesses on how the Paracels were taken by China by force and descriptions of heroic actions by South Vietnamese sailors.
Public meetings have been held to commemorate the battle and there are calls to recognise the "martyrdom" of the fallen soldiers and offer support to their families.
Just months ago, such moves would have been unheard of. The authorities in Hanoi have been extremely careful not to offend Vietnam's giant neighbour - and are also fully aware that nationalist sentiment can get out of hand.
Anti-China protests in which participants have shouted slogans such as "The Paracels belong to Vietnam" have been quickly dispersed in the past.
As Vietnamese media remains tightly controlled by the Communist Party, the green light to address the issue of the battle may have come from above.
Prime Minister Nguyen Tan Dung reportedly told a meeting with leading Vietnamese historians at the end of December that the government was planning activities to commemorate the 1974 event, as well as the 1979 border war with China.
He also urged to include "these historical facts" in school textbooks.
Emeritus Professor Carlyle Thayer from the University of New South Wales in Australia says raising the profile of the 1974 conflict "has more to do with shoring up domestic legitimacy by undercutting the overseas Vietnamese supporters of the Saigon regime who, of course, memorialise this battle".
Ho Van Ky Thoai, a former rear admiral in the Saigon navy and one of the commanders of the 1974 battle who now resides in the United States, agrees there has been "a shift in the Vietnamese government's approach to the subject".
"They have come to realise the clear danger of being swallowed by China. Unfortunately, it is years too late," he said, adding that the best the Vietnamese government could do is to quickly give the South Vietnamese soldiers the highest recognition they deserved.
Sceptics also point out that this might be just a patriotic card cleverly played by Vietnamese leaders to distract the public from problems such as the economy and rampant corruption.
Some of the largest corruption trials involving high-ranking party officials are slated to take place this month, and as the Lunar New Year approaches complaints about living standards are once again surfacing.
But for many this new move is an indication of Vietnam's attempt to consolidate its territorial claims in the face of China's increasingly assertive activities in the South China Sea.
"Vietnamese people are facing a danger of aggression and humiliation [by China] like never before in the South China Sea," warns historian Nguyen Nha.
New fishing rules by China that took effect on 1 January require foreign fishing ships to obtain approval to enter waters it has placed under the jurisdiction of the Hainan provincial government, including those surrounding the Paracels.
Experts say the rules are likely to create incidents with Vietnamese fishermen who consider the waters around the islands their traditional fishing grounds and regularly accuse Chinese authorities of harassment.
Vietnamese media have raised the tone of their reports on China's new fishing regulation, which Hanoi has called "illegal and invalid".
But "it is the reported instigation of Vietnamese authorities encouraging Vietnamese fishermen to fish in the waters around the Paracels that could lead to conflict", warns Prof Thayer.