Seventy years ago, the incredible feat of transporting heavy two-tonne cannons across winding mountain ranges and steep ravines to reach the battlefield in the Điện Biên Phủ Campaign was a journey fraught with hardship, toil, and sacrifice for Vietnamese soldiers.

The movement of cannons into the Điện Biên Phủ battlefield was a miracle that surpassed the enemy's understanding.

The poignant song 'Hò kéo pháo' (Heave Away The Cannon), composed by Hoàng Vân, vividly depicts the hardships and unwavering determination of Vietnamese soldiers during the Điện Biên Phủ Campaign 70 years ago and the historic cannon-pulling route has since become legendary.

One of the lines from the song is: 'The mountain is formidable, but our strength is more formidable. The ravine is deep, but our anger and resentment are deeper.'

Over seven decades ago, Pha Đin Pass, in the northern province of Điện Biên, served as a critical supply route for transporting weapons, ammunition and provisions for the Vietnamese infantry and artillery during the campaign.

Previously spanning 32 kilometres as part of National Highway No. 6, this pass acted as the gateway to Điện Biên Province. At 1,648 metres above sea level at its highest point, with sheer cliffs on one side, a deep abyss on the other, the pass climbs a gradient of up to 10 per cent, reaching a daunting 19 per cent at certain points.

The road along the pass, is treacherous, twisting over sharp corners and countless hairpin bends.

Despite these challenges, Vietnamese soldiers persevered in transporting weapons and provisions to the Điện Biên Phủ battlefield via the pass under fire from relentless air raids by the French air force aimed at impeding their progress. Yet, these adversities failed to dampen the resolve and fortitude of the Vietnamese soldiers in their mission to move cannons into the campaign.

Điện Biên soldier Lê Hữu Thảo shares with a reporter the hardships and challenges on Pha Đin Pass. VNS Photo Văn Tâm

Lê Hữu Thảo, a 93-year-old Điện Biên soldier from Thiệu Giao Commune, Thiệu Hóa District, Thanh Hóa Province, vividly recalls the intense bombing endured by Pha Din Pass, a crucial point heavily targeted by the French army in their attempts to sever supply lines of food and weapons.

Every day, French planes relentlessly bombed the pass area, dropping hundreds of munitions in their efforts to obliterate this vital supply route. Nowadays, Pha Din Pass has been lowered and widened, however, it remains a legendary route where Điện Biên soldiers once pulled cannons with sheer human strength.

Among the routes used for pulling cannons, one stands out as particularly special: A 15-kilometre stretch from the Nà Nham forest gate over Pha Sông mountain peak down to the Tấu and Nghễu communes, now part of Nà Nhạn Commune in Điện Biên Phủ City. Remarkably, this stretch of road was constructed in just 20 hours by a combined force of 5,000 officers and soldiers.

On this challenging route, heavy cannons, each weighing over two tonnes, were carried to the summit of Pha Sông at 1,500 metres.

After nearly ten days and nights of super-human effort, the army's cannons were successfully brought into the battlefield, closing in on the enemy's positions. However, upon assessing the enemy's situation, the Điện Biên Phủ Front Command made the strategic decision to shift from the approach of 'strike quickly, win quickly' to 'strike firmly, advance steadily'.

So the troops had to undertake the arduous task of pulling the cannons out once again. While pulling the cannons in was challenging, extracting them from the position proved to be even more daunting. The process demanded utmost caution, with any mishap, such as a snapped rope, resulting in the cannon plummeting into the abyss below.

During one such incident a young soldier named Tô Vĩnh Diện courageously leapt into action, using his own body to block the sliding cannon and prevent disaster and his selfless act has been immortalised in history as a legend, symbolising the indomitable spirit of the Điện Biên soldiers. Inspired by soldier Tô Vĩnh Diện's heroic sacrifice, the entire front rallied together to ensure the safe extraction of the cannons.

Điện Biên soldier Phạm Đức Cư, hailing from Nam Thanh Ward in Điện Biên Phủ City, vividly recounted the gruelling final stretch of the cannon-pulling journey.

He said: "Our march was incredibly tough. When we reached Điện Biên, approximately 15km from the Điện Biên Phủ base group, we had to manually pull the cannons. That was the most challenging part of our military service. We will never forget the sections of the road at the Bảy Tời, Ông Mậu, Suối Ngựa, and Voi Phục slopes, as well as the heroic sacrifice of Hero Tô Vĩnh Diện."

Vietnamese troops pulling cannons into Điện Biên Phủ. File photo

Despite facing countless obstacles and enduring hardships, the 75mm cannons, 120mm howitzers, and 105mm cannons all simultaneously unleashed rounds into the Him Lam resistance centre, signalling the commencement of the Điện Biên Phủ Campaign at 5 pm on March 13, 1954. The French army had never anticipated that the Việt Minh forces could maneuver the cannons so close to the battlefield and this unexpected development significantly contributed to the victory of Điện Biên Phủ.

The entire nation is now ready to commemorate the 70th anniversary of the Điện Biên Phủ Victory.

During a trip to Điện Biên Phủ City, Nguyễn Văn Toàn, a tourist from Đà Nẵng City, said: “Having the opportunity to visit the land of Điện Biên, to explore its historical relics, I am deeply moved, proud, and grateful to the previous generations who fought for the independence and freedom of the nation.

"Especially, visiting the cannon-pulling monument, I am deeply impressed by our ancestors, who, with their humble strength, pulled tonnes of cannons across countless high passes and deep ravines to reach the battlefield safely."

The echoes of war have faded into history and the route once traversed by brave soldiers to haul cannons to Điện Biên starts from the majestic Pha Din Pass and culminates at the memorial site of Hero Tô Vĩnh Diện, who sacrificed himself to secure the cannons. Situated approximately 20km north of Điện Biên Phủ City, a complex of statues now graces the Bó Hom Hill, paying tribute to the heroic artillery unit led by Hero Tô Vĩnh Diện. This monument serves as a testament to the legendary cannon-hauling route of the past, inspiring future generations.

To enrich the experience of visitors eager to delve into history, a museum showcasing some artefacts used by Vietnamese soldiers during the cannon-hauling efforts 70 years ago is adjacent to that cannon-hauling mon