The ﬁrst phase of the Tet Oﬀensive began in the fall of 1967. Because the ﬁnal plan and authorization was not issued until December 1967 and planning had been so secretive, PLAF units in particular had little time to prepare for highly visible and dangerous missions. Many chains of command had to be reorganized as units were reconﬁgured to meet whatever operation they were assigned. Operational security was paramount to the success of the initial Tet attacks. Such stress on secrecy, however, had the unintended consequence of leaving many oﬃcers and units in the dark as to how their particular mission ﬁt into a broader operation. Moving large amounts of material and thousands of troops along inﬁltration routes across the DMZ and down the Ho Chi Minh Trail was also a major security hazard. New recruits were needed to ﬁll out under-strength units, which trained hard to make the paradigm shift from guerilla-style tactics to urban warfare methods required for ﬁghting in the cities. Preparing for the oﬀensive was a tremendous and risky undertaking.