(VOVWORLD) - A secret wartime site, the Cipher Bunker of the General Staff of the Vietnam People’s Army, has been opened to visitors for the first time. The bunker played a crucial role in securing coded communications, helping to maintain command and coordination of military forces across battlefields nationwide during the resistance war.
 The gate of the Cipher Bunker (photo: Kim Lieu/ VOV5) |
“The Cipher Bunker of the General Staff was built in 1966. Covering 37 square meters at a depth of 4-5 meters, it comprises 2 workrooms and 1 equipment room. The bunker was designed to withstand a nuclear bomb, radiation, and hazardous chemical gas. It had a steam-based air conditioning system, ventilation, toxin filters, natural airflow, and anti-interference systems. It can accommodate 10 to 15 people at a time.”
Tour guide Nguyen Khanh Van introduces visitors to the historic bunker, which is located deep beneath the Thang Long Imperial Citadel World Heritage Site in Hanoi.
 The stairway down to the Cipher Bunker (photo: Kim Lieu/ VOV5) |
It is part of an underground system that includes the Central Military Commission House and Bunker and the Combat Command Bunker. The underground system is where the General Staff worked and made crucialdecisions that led to Vietnam’s national reunification in 1975.
During the war, the Cipher Bunker was alifeline of communications where secret documents, reports, and coded directives were transmitted continuously to and frommilitary forces on the battlefield. Itsmost intensive activity was reported in December 1972, when US air forces bombed Hanoi and Hai Phong relentlessly.
 The bunker is designed to withstand a nuclear bomb, radiation, and hazardous chemical gas. (photo: Kim Lieu/ VOV5) |
Associate Professor Dr. Nguyen Manh Ha, Former Director of the Institute of Party History at the Ho Chi Minh National Academy of Politics, said: “One of the most important agencies was the Cryptographic Department. It received and transmitted tens of thousands of coded messages during the resistance war. The battlefields received prompt, secret orders. Even during bombings, the cipher staff worked underground around the clock to ensure smooth command and communication between Hanoi and the battlefields, playing an essential role in the nation’s victory.”
Revisiting her former workplace, Dang Thi Muon, a codebreaker of the Cryptographic Department, recalled: “We processed countless telegrams, such as those from leader Le Duan, Pham Hung, and Le Duc Tho, and messages from the Central Office for South Vietnamto the North, and vice versa. The codebreaking team worked non-stop around the clock. These telegrams were extremely important, giving instructions down to the hour and minute, continuously.”
 Display of items used by cryptographic officers and soldiers (photo: Kim Lieu/ VOV5) |
The Cipher Bunker has been restored nearly to its original state, including a display of items used by cryptographic officers and soldiers – “Top Urgent” and “Most Urgent” stamps, coded telegrams, cipher notebooks, fountain pens, and document briefcases. An exhibition space plays documentary films and audio recordings to let visitors relive historical moments.
Dr. Le Thi Minh Ly, Vice President of the Vietnam Cultural Heritage Association, said: “During the war, some matters were never recorded, for security reasons, including the construction of this bunker, which remained a state secret. It was very difficult to restore this place. We’ve breathed life into this heritage site with panels of information that’s accurate and made easy to understand.”
 Display of items used by cryptographic officers and soldiers (photo: Kim Lieu/ VOV5) |
Tourists can examine coded telegrams and photos of the codebreakers who worked day and night and reflect on the war’s harshness and the resilience of the Vietnamese army and people.
Since opening on August 19, the Cipher Bunker has been welcoming crowds of visitors.
“Stepping into the bunker, we felt a solemn and heroic atmosphere and a spirit of patriotism.”
“I went down into the bunker, and was very surprised because it was much larger than I had imagined. I was filled with keenness.”
 Display of secret messages (photo: Kim Lieu/ VOV5) |
The Cipher Bunker opening inside the Thang Long Imperial Citadel highlights this World heritage site as safeguarding vestiges of a millennium-old history and housing revolutionary relics that nurture Vietnam’s patriotic tradition.