Battle of Tri Phap
The Battle of Tri Phap took place from 12 February to 4 May 1974 when South Vietnamese forces successfully launched a pre-emptive attack on a North Vietnamese base area in Dinh Tuong Province before North Vietnamese forces were scheduled to be moved to the area . 
<triplet> Battle of Tri Phap <subj> 4 May 1974 <obj> point in time