A Day in the Iron Triangle Secret Zone

Michael Do

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Ngả Năm Chuồng Chó

Kien[1] Base was built in the middle of the Iron Triangle secret zone about two kilometers from the small town of Ben Cat. The Iron Triangle is a small part of the larger triangle between the Thi Tinh River on the east and the Saigon River on the west. The acute angle is the meeting point of two rivers at Ben Cat.

On the north side, a dirt road from Ben Cat bridge ran along the river to Dau Tieng and farther to the Cambodian border. This had been, for decades, the supply route of the enemies to many famous secret zones such as war zones D, Long Nguyen, Boi Loi, Ho Bo, and Tam Giac Sat (Iron Triangle), to name a few!

 In 1967, near the Ben Cat district compound, a fierce battle occurred – Operation Cedar Falls – between Viet Cong and units of the ARVN 5th ID and US 1st ID amid the Iron Triangle. Two years later, we found the ruins of three armored vehicles: one M-41 tank, two M-113 APCs, and various items of American soldiers at the spot where five narrow trails converged. We gave it the nickname “Ngả Năm Chuồng Chó” (five-way intersection at the dog kennels), after the name of the very famous red light district in the north suburb of Saigon.

The part of the Iron Triangle near Ben Cat was narrow, about 120 square miles, but there were countless bombs, shell craters, and numerous land mines of various types. Viet Cong planted the mines without having a map. Months or years later, dense bushes, elephant grass, and vines covered the trails, and there was no safe place to set foot. Even VCs were killed by their mines!

The enemy’s big units withdrew to safe regions on the other side of the Viet-Cambodia border. They avoided contact with the ARVN; their operations were reduced from major offensive to small-scale guerrilla harassment. In the first phase of the pacification campaign in the region, in June 1970, my Battalion was ordered to clear the zone and build a small base to monitor the enemies’ activities. 

We unloaded at the dirt road by the bank of Thi Tinh River. A large bulldozer D-10 of the 5th Field Engineer Battalion led the way, followed by our troops. The monster plowed deep into the soil to destroy the mines. The infantrymen watched to find any booby traps or mines that were exposed. They must be very careful because the bulldozer might have missed some. We proceeded slowly, very slowly. It took us two days to clear a distance of more than one kilometer from the starting point to “Nga Nam Chuong Cho” where we found the burned tank and APCs. 

The Iron Triangle was a very dense forest. The trees were tall and big, making a double-canopy above. Thorny vines and rattens scrambled through and over other trees. The jungle was impassable unless you followed a guide and put your feet precisely on his steps.

The first day of the operation was OK. Soldiers removed hundreds of homemade mines along the track without incident. Some mines were made in a simple way. Viet Cong put nails and pebbles mixed with C-4 explosives in used cans of different sizes and plugged a fuse into them. That’s all. They were not as fatal as mines supplied by the army. Within a radius of five meters, they might kill a person if the fragment hits his vital organs. The scariest mines were those made of unexploded cannon shells. This type was so powerful that it could convert a man into tiny bits of flesh and bone.

The bulldozer had plowed a circle around the dead tanks for my Company to set up a defense perimeter. We did not dig up fox holes for fear that some mines might not be cleared yet. Neither did we set the claymore mines as usual. The sky was unceasingly lit up with flares the whole night. It was like the daytime. We lay down wherever we felt safe from the snipers. Of course, that was not the time for a good sleep. The enemy’s commando could easily sneak into our positions. We stayed up all night.

The following day, Lieutenant Nguyen Hưu Đat, my CO, was shot in his head by a sniper. The bullet hit the helmet at a slight angle and only slid a little through the skin of his left upper head. He was evacuated at once, and I assumed his authority.

I was one of four officers who graduated from the 1st class of the Polwar College and were assigned to this 4th Battalion. Duong Quang Boi was the commander of the 16th Company; Quach Ke Nhon was XO of the 14th Company; Mai Thanh Tong was the S-5[2] officer of the Battalion.

After the counter-ambush at Bunard, I had been the candidate for a company commander position. Now, it was my time to face the challenge and move forward in my military career.

Captain Hien moved two companies farther up north, leaving my Company to safeguard the HQ Company and a Company of the Army Engineer Corps to build the base. They worked hard day and night, clearing an area 150 meters in diameter. At the center, they built three underground bunkers. Their roofs were covered with one layer of PSP[3] and five layers of sandbags. Thus, they could stand the bombards of 82 mm mortar or B-41 RPGs. The first defense perimeter comprised eight smaller bunkers to house the soldiers; the second was layers of barbed wires and concertina wires; and finally, a layer of claymore mines and flares. We put concertina wires to isolate all the bunkers and left the narrow gates between them to prevent the commando from infiltrating at night. I was issued an 81 mm mortar and a 107 mm recoilless rifle.

The Engineer Company and the HQ Company withdrew when the base was finished. I became the king of the base with 125 soldiers under my command. We sent a platoon to the intersection of the dirt route to be a permanent outpost. Two other platoons would go on patrol within a radius of three miles from the base. They left the base early in the morning and did not return until evening.

One day, my men discovered a hidden bunker. It was built underground and could not be seen even though we were on top of it. We just were lucky. It was empty and uninhabited for a long time. A soldier found some women’s underwear and leftover foodstuff.

Viet Cong built many bunkers in their secret zone for their guerrillas to temporarily stay when they passed the area. Guerrilla teams were made up of two males and one female. It was called “Tam Tam Chế” (the trio formula), the lowest cell in the Communist party grassroots organization – the cell. Each side of the bunker had a small opening enough to watch out and to slide the rifle barrel to fire. From the bunker, they could see very clearly what happened outside, but the outsider was unable to see anything. It was hard to detect the bunker and was much harder to destroy with small arms. If the enemies knew that we would call artillery, they had enough time to move to another bunker or to run away. Of course, we could beat them, but with relatively high costs.

One day, Lieutenant Nguyen Trong Thuy reported that a soldier was missing when the 3rd Platoon withdrew from a recon operation. We had not heard any fire shot nor any explosion. I thought it was understandable because of the dense forest; the man might get lost. That was the case. He ran toward us from the edge of the forest, breathing heavily. His face was pale.

“Lieutenant,” he stammered, “I saw they were fucking.”

“You are kidding,” I burst into laughing, “Since you are so scared, you would see an evil thing.”

“No, Sir,” He said, “I saw it with my eyes. They are a male and a female Viet Cong.”

“Why didn’t you shoot them?”

“I had just pulled my rifle, and they heard the noise, pulled up their pants, and ran away in a blink of an eye.”

I reported the incident to Captain Hien. He laughed,

“He told the truth. It is very normal with the guerrillas.”

The day was long, as if it never ended. We did not know what to do to kill the time. Going down the bunker, going up the bunker, looking up at the sky, then going down again. It was so boring.

At times, Viet Cong approached the base, hiding in the thick tree canopy, and used a loudspeaker to persuade our soldiers to defect.

“Listen, listen. The troops of the Liberation Front were surrounding this base and will annihilate all of you in the coming days. Drop your weapons and surrender. The revolutionary army is tolerant and will treat you humanly.”

Sometimes, they shelled mortars to the base, particularly each time a chopper landed to resupply. We just jumped to the bunkers and fired back. I ordered the machine gunners to aim at the canopy to scare their observers, if any. Our recon platoon killed two enemies when they were moving to the base.

Corporal Nhan, the cook, made me a cup of coffee every morning and two hot meals per day. There was nothing but rice and dried fish for meals: sour soup with dried fish and dried fish on the fire or dried fish fried in oil. Nhan was too old to be drafted. He must be above 60 at that time. There had been trouble with his identification document, and he had to join the army. Nobody bothered to review his case. Lieutenant Dat kept him at the CP as the cook, and I did not want to replace him. 

The base got weekly resupply by helicopter. I would have for myself a box containing newspapers, magazines, cigarettes, a can of meat, letters from my family, and – don’t tell anybody – a bottle of rice wine.

The night before the supply day, I sat by the radio expecting to hear the order to get ready for unit exchange. One month passed. We were to be replaced by another company after fifteen days. Stationing in the same small spot was not what we – as combat infantry – expected. It was so bad. We considered ourselves prisoners exiled on an island. I read a series of Chinese Kung Fu novels until I could memorize every name in the books. I listened to any kind of music until I memorized all the lyrics. But it was boring, boring, boring! I knew some of my men at the outpost took a high risk to go to the market during the day.

At the seventh resupply, we were here for almost two months. I was in a desperate mood. While Lieutenant Quoc, the battalion operation officer, was online, I started my voice,

“This is the voice of the 15th Company. To begin our broadcast session tonight, please listen to the song “Đường Trường Xa”. This song is for the Battalion Commander, Captain Hien… “

“Đường Trường Xa” (The Long Way) was the official song of the ARVN which I altered the lyrics to complain about the extended stay at this base!

At midnight, I was woken up to listen to Quoc, who conveyed the message from Captain Hien,

“Dare you not to revolt! He would put you in jail for thirty days and send you to Phuoc Long. Understood? Tomorrow, make sure the LZ[4] is fully secure. There will be a special gift for you. A very special gift,” Quoc stopped talking and hung up the headset, did not let me ask a question.

I could not sleep that night. What was the special gift? Might it be a bottle of Cognac that Captain Hien knew was my favorite? No way! Hell, no way! I had just upset him. Or might it be the infrared night vision that I had requested? This seemed possible! The unit defending Lai Khe had just been equipped with the night visions.

Before nightfall, I sent two platoons out to secure the landing zone. The jungle at night was deadly quiet! There was no sound of any animal or the rustle of leaves. The thunder of the war had scared away all kinds of animals and birds. I fell into a short sleep. Now and then, I called the Platoon at the outpost to make sure the duty guard was in his position.

Infantrymen were at a disadvantage compared to other branches of the armed forces. We went on operations all year round, walked a dozen kilometers in the daytime, and stood guard for at least three hours at night. We never had a sound sleep. Rainy or sunny, we had only a set of fatigues on. We had a poncho to cover in the rain, to make a tent at night, and to wrap up our bodies when dead! On our back, there were no less than 20 kilograms of weapons, three units of ammo, a shovel, a claymore mine, an M-72 rocket launcher,

food rations, and miscellaneous personal items. The weight limited our mobility.

On the contrary, the enemies did not have to go on long periods of search operations. They knew their targets. When the target had been chosen, they gathered and moved quickly to assault after midnight and withdrew before sunrise. That was the same as when they ambushed our moving troops.

I subdued my worry and turned over on the nylon hammock, trying to sleep again. I couldn’t. Beside me, the radioman was snoring at the other corner of the bunker. The radio kept sounding the static “pip, pip!”

I happened to think about my wife, whom I married a year and a half ago. My first son, Loc, will be one this September. I had been lucky to get wounded and stayed home on and off during three months of my treatment. It was rare happiness when I could hold and feed my son in his first months of life.

When I was an XO, I could sometimes have a brief leave to go visit my family at Vung Tau. Now that I had a heavy responsibility as a commander, I would not leave my Company even for a day.

Another night passed. The sunbeam came through the roof of the forest and shone upon the base. On the other side of the Thi Tinh River, townsfolk prepared for a new day. I guessed Miss A Mui was organizing her rolls of fabric on the wood stand; Miss Ut Tron and her tailor apprentices might be pulling her sewing machine from the closet. I happened to remember the flavor of a bowl of beef noodles at the kiosk near the road that led to Lai Khe.

Đệ, my radio operator, turned the volume for me to report the situation and receive the new orders from the Battalion.

“Lieutenant,” said he, “Uncle Ba reminds you to keep the helipad maximum secure. There will be a special supply.”

“Nothing but seven more days’ supply of dried meals.”

“Something very special,” De said, “the S-3[5] insisted and repeated many times. You should better talk with him.”

“33[6], this is 51[7], over.”

“51, this is 33. Your Whisky and Sierra [8] came yesterday. 74[9] allowed them to board the supply chopper to visit you at the base. Be aware of the mortars.” Quoc said.

It was a big surprise I had never dreamed of! Captain Hien was very flexible in dealing with the soldiers’ family matters. Many soldiers had wives living with them each time we returned to the home base at Lai Khe. Soldiers would have fifteen days of leave per year to visit their families. But the women did not want to stay in their village and wait for their loved ones. They wanted to be close to their husbands to share sweetness and sorrow, even the danger. Some did not have a place to live since the war destroyed their village!

At our rear base at Lai Khe, there was about a “platoon” of those women and their children. Captain Hien ordered the Aspirant Sung – who was in charge of the rear base – to take good care of those people no matter what. They became part of our Battalion!

As far as I knew, the guerrillas operating in this forest had only 61 mm mortar. Their Phu Loi Battalion had 81 mm, but they were partly disbanded and did not exist in this area.

At 06:45 a.m., I ordered the machine gunners and mortar squad to get in their positions. I also asked Corporal Quy to get two helmets ready and two body armored vests at the helipad. Radiomen began to get busy sending messages between the Company and the Battalion. Sergeant Hung threw a green smoke grenade as the helicopter pilot requested. The noise of the rotary wing was closer and closer. The UH-1B of the US Big Red One approached, lowered its altitude,  and landed. I was the first to jump to the chopper door, where the crew chief was helping my wife to get down. She was holding the child. I put the helmet on her head and wrapped her in the vest. Quy took the child and guided my wife to my bunker.   I did not have more time to talk now. The chopper would not stay long. Soldiers helped to unload the supply quickly. I had to work with Sergeant Thanh, the logistics NCO. He handed me a stack of paper to sign. Everything happened real fast, just in three or five minutes; then the chopper took off before we could hear the departing sound of the mortars from the west of the base.

I ran into my bunker, “Don’t be scared. This bunker can stand the bombing,” I comforted my wife, “you are so daring.”

“We miss you,” my wife smiled, “It has been half a year since I have not seen you.”

“Well, they are coming. Lean on the wall. You will be used to it.”

Boom! Boom! Boon!

Most of the shells landed outside the first barbed wires; one exploded right next to the well within the inner circle.

I could not fire mortars in that direction where I suspected the enemy existed because we had a platoon patrolling there.

I shouted to Thoai, the radioman, to contact the 2nd Platoon.

“Thoai, tell Aspirant Chieu to search farther to his west at 10 o’clock. Charlies must be somewhere in this direction.”

When things were quiet, I spent time with my wife and child. Hoa was wearing the uniform; the helmet was still on her head. I hugged and kissed my child,

“Little soldier! You are as brave as any young man. Are you scared?”

“We arrived yesterday afternoon,” my wife said, “Knowing you are on operation, we were almost leaving, but Captain Hien said there would be a supply helicopter and he would let me ride on. He also gives you a bottle of Hennessy. Mother made this lemongrass peppered chicken for you and some other things.”

Loc was nine months old. He could walk and started to talk a few words. He stared at me; his tiny hands touched my face as he babbled.

I kissed him again and then got out of the bunker to check on the new supply.

“You distribute the ammo and dried meal to the platoons. Tell me what we get?” I asked Hung, the Company Sergeant.

“Sir, there are mortar shells, machine gun bullets, Dried rice, and canned meat. You have a box of papers and canned fruit.”

“Please, tell Mr. Nhan to prepare dinner for us, the CP. By the way, don’t forget to invite the platoon leaders.”

At noon, Lieutenant Thuy, Aspirant Chieu, and his 2nd Platoon returned from their ambush. The 1st Platoon of 1st Sergeant Tiet stayed until late afternoon; they would move to another location to set up the night ambush. The 3rd Platoon was still stationed at the outpost.

Lieutenant Nguyen Trọng Thuy graduated from the 27th class of Thu Duc Infantry School. This young man was easy-going, short, and had dark skin. I picked him as my XO. First Sergeants Tiet and Tri led the 1st and 3rd Platoons, respectively. Aspirant Nhon had just been assigned to the Company. I let him go with Sergeant Tiet. The ARVN had expanded in these years, and there were not enough officers to fill the ranks. Even the strength only reached about 80% of the theoretical number designated by the book. Besides, we suffered a high rate of desertion. The 5th ID territory was too close to Saigon. Soldiers could sneak out of the gate, hop on a motorbike, and disappear.

The 4th Battalion under Captain Hien has been improved regarding the deserter problem. He was flexible in the policy by letting soldiers go on leave if their families came and signed a promissory note that they would convince the soldiers to return to the unit on time. He warned his officers to be concerned about the soldiers’ benefits. The S-5 officer, Lieutenant Mai Thanh Tong – a classmate of mine – worked twice as hard as he did previously under other commanders.

We sat on the wooden boxes around the makeshift table as Corporal Nhan brought in the food. I poured the cognac into a mug and drank a small sip before passing it to others. The food my mother made was delicious. It was how we always did on the battlefield; we shared anything we had and never kept to ourselves. It was the most delicious meal we had had for months. 

“Tonight, Phan (my radioman) will share the bunker with Lieutenant Thuy,” I said, “Quy will hang another hammock in my bunker.”

“I thought Sister Hoa and you will sleep on the same hammock!” Lieutenant Thuy made a joke.

“And must be sixty-nine,” Quy added!

“Hey! No more kidding,” I knocked on Quy’s head, “how do you know about the adult stuff?”

“Don’t underestimate him,” Tiet said, “He was the boss at the Truong Minh Giang market.”

“Tonight, out there, Viet Cong shoot mortars; in here, another bombard. Who could stand this!”

“Well, don’t complain; do it yourself then.”

“Lieutenant, please give me a couple of days to visit my family after the operation. I have not seen them for almost a year.” Sergeant Hung took advantage of this joyful moment to ask for a favor.

“OK, consider it. Bottom-up!”

Around the table in the open air, we talked, laughed, and made a joke with one another until late at night. The war made us from young folk into tough soldiers. We did not think of what might happen; we just enjoyed what we had in hand. How many more years the war would end? And, who among us would die tomorrow, after tomorrow; who cared!


[1] The base was named after Major Chau Minh Kien, Commander of the 1/8 Battalion, KIA in 1970.

[2] S-5: Political Warfare Officer.

[3] PSP: Pierced Steel Planking, the material used to build temporary runways and landing strips

[4] Landing Zone.

[5] S-3: Operation Officer.

[6] 33: Radio code for Battalion Operation Officer.

[7] 51: Radio code for 15th Company Commander.

[8] Whiskey and Sierra: Disguised for ‘wife’ and ‘son.’

[9] 74: Radio code for the 4th Battalion Commander