Prepare yourselves for the offensive! Tonight's tweets will cover the lead-up to the moments before 1968 Tet Offensive began in Phu Yen Province. Tomorrow night's tweets will address the actual fighting. Follow the hashtag #1968TetPhuYen. https://twitter.com/DrRobThompson/status/1089922056051920896

Today marks the 51st anniversary of the 1968 Tet Offensive. Known to the North Vietnamese as the 1968 General Offensive and Uprising, this effort marked the Hanoi’s second attempt to unfits North Vietnam with the South by through a military solution. #1968TetPhuYen

The General Offensive and Uprising emerged out of General Secretary Le Duan's plan to exploit perceived American and South Vietnamese military and political weaknesses through a massive, countrywide armed assault on South Vietnam's major urban centers. #1968TetPhuYen

As envisioned by Hanoi, the General Offensive and Uprising would use conventional military and guerrilla forces to destroy enemy units and take cities, thereby causing the South Vietnamese people to rise-up against Saigon. Le Duan thought this would end the war. #1968TetPhuYen

The execution of Le Duan's plan in Military Region 5 became the primary concern of PAVN's Major General Chu Huy Man. To "liberate" Phu Yen Province he called for the taking of the province capital, Tuy Hoa City by PAVN & People's Liberation Armed Forces battalions. #1968TetPhuYen

Hanoi envisioned the offensive beginning on the first night of Tet. However, the use of two different calendars meant Tet began on two different nights. In the North the holiday started on the night of 30-31 Jan, while it began on the night of 29-30 in the South. #1968TetPhuYen

Unaware of the calendar issue, Military Region 5 prepared to commence the offensive on the night of 29-30 January. In Phu Yen, the 95th PAVN Regiment and 85th PLAF Local Force Battalion readied themselves. #1968TetPhuYen

PAVN and PLAF preparations were noticed by the Americans and South Vietnamese. In Phu Yen's Tuy Hoa District, officials noted an uptick in enemy movement. U.S. advisors recognized an enemy plan was afoot, but they did not know when it would transpire. #1968TetPhuYen

The major American military effort in Phu Yen, Operation Bolling, was well underway. Having begun in September 1967, Bolling involved elements of the 503d Infantry Regiment of the 173d Airborne Brigade protecting people and rice production in the Tuy Hoa Valley. #1968TetPhuYen

Bolling's area of operations covered much of the Tuy Hoa Valley, the very space Man's forces would need to traverse before reaching Tuy Hoa City. Yet the close proximity of a base area and the cover of darkness gave his troops an edge. #1968TetPhuYen

Thus with the cover of darkness, and assistance rendered by local guides, the 5th Battalion of the 95th PAVN Regiment, along with supporting units, reached the rice fields just outside of Tuy Hoa City without alerting any opposing forces. #1968TetPhuYen

Now the 5th Battalion took up positions near its two objectives: the province prison and the adjacent Tuy Hoa North Airfield. The Battalion intended to liberate prisoners while destroying the U.S. Army artillery battery and aircraft located at the airfield. #1968TetPhuYen

Once in position, the 5th Battalion's two mortars dropped shells on the nearby 47th ARVN Regiment compound. That act signaled the commencing of the offensive, and sent American and South Vietnamese officials scrambling. Yet nothing happened after the shelling. #1968TetPhuYen

Instead of following with a ground assault, the 5th Battalion waited for the 85th PLAF Local Force Battalion to make the first move as originally planned. That force was to strike the city center. Yet the 85th canceled its attack after observing an ARVN roadblock. #1968TetPhuYen

Therefore the 5th Battalion waited and waited in hopes the 85th would act. The 5th Battalion's patients ended, however, as dawn threatened to expose the units's position. Not wanting a premature end to the offensive, the 5th's three platoon made their move. #1968TetPhuYen

Early on 30th January, two platoons made for the prison, while the third platoon assaulted the American artillery battery. There the third platoon penetrated the perimeter that separated Battery C of the 6th Battalion, 32d Artillery from the rest of the province. #1968TetPhuYen

The third platoon occupied a bunker and disabled at least one artillery piece. The defending U.S. Army artillerymen recovered from the initial shock of the PAVN assault, forming a new line while the god-like firepower of M42 Dusters largely contained the invaders. #1968TetPhuYen

Meanwhile, word of the PAVN assault reached the American rapid reaction force in Phu Yen, D Company of the 4/503d Infantry. After a quick planning session, that force's spearhead boarded two Chinooks and made for Tuy Hoa North with great haste. #1968TetPhuYen

The first Chinook to arrive at the airfield received withering enemy fire. After losing an engine, the twin-rotter helicopter bounced off the ground before grinding to a stop. All the occupants somehow survived. The second Chinook did not attempt at landing. #1968TetPhuYen

Instead, the second Chinook deposited its troopers at another airfield. From there, Huey's later transported the men to Tuy Hoa North Airfield. #1968TetPhuYen

After entering the compound, the spearhead quickly pushed the 5th Battalion out. Air support from a C-47 Puff raked the 5th Battalion in the fields outside the artillery battery. By now, PAVN’s assault on the prison had also failed. #1968TetPhuYen

More elements of the 4/503d also arrived at Tuy Hoa North by now. Battalion commander LTC James H. Johnson, 173d Airborne Brigade commander GEN Leo H. Schweiter, Deputy Senior Providence Advisor LTC Vernon Walters, and Province Chief Nguyen Van Ba were on scene. #1968TetPhuYen

The battle now shifted to a hill overlooking Tuy Hoa North Airfield. Called Cemetery Hill by the Americans, elements of the 5th Battalion entrenched themselves at that location. American soldiers and PAVN regulars engaged in a close-quarter fight for that hill. #1968TetPhuYen

The Americans prevailed – taking Cemetery Hill and forcing the North Vietnamese to flee. The 5th Battalion had established its command post in the nearby hamlet of Binh Tin. From there, the remaining PAVN soldiers now continued their fierce resistance. #1968TetPhuYen

South Vietnamese and South Korean units arrived to help the Americans contain the North Vietnamese in Binh Tin. The Allies used loudspeakers to call for PAVN’s surrender and in hopes of getting civilians to leave. Unsurprisingly PAVN refused to give up. #1968TetPhuYen

The Allies then fired tear gas into the hamlet. As the tear gas blanketed the hamlet, D Company donned gas masks and assaulted the PAVN positions. Intense fire from well-protected PAVN soldiers and the fogging of gas masks caused the American attack to fail. #1968TetPhuYen

With mounting casualties after a nearly day-long battle, the Allies resorted to airstrikes to break the stalemate. USAF F-100 Super Sabres delivered 250 and 500 pound bombs, as well as napalm, into the hamlet. #1968TetPhuYen

The first sortie placed a 500 pound bomb directly into the 5th Battalion’s command post – killing commanders and seriously weakening resistance. Without knowledge of that information, however, the Americans stayed back and planned for an assault the next morning. #1968TetPhuYen

While the Americans prepared for their assault, the 47th ARVN Regiment and two RF companies cleared the cratered hamlet. By morning of the 31st, little remained of the hamlet and the 5th Battalion. The first phase of the Tet Offensive was over. #1968TetPhuYen

The first phase cost the 5th Battalion dearly with 189 dead and 31 captured. Having started with 300 troops, the loss of 220 from its ranks wrecked the 5th Battalion. Later, the infusion of replacements meant the battalion’s participation in the third phase of Tet. #1968TetPhuYen

The Americans suffered less than the North Vietnamese. In all, 4 artillerymen and 14 men of D Company died. The dead included the officer in command of the 319th Airborne Field Artillery Battalions’s radar station at Tuy Hoa North, LTC Robert E. Whitbeck. #1968TetPhuYen

Correction: instead of PAVN "platoons," I should have written "companies." As in the third company assaulted the artillery battery.