Dien Bien Phu was doomed from the start, because the French thought they were going to replicate the Battle of Nà Sản. At Nà Sản, the French repeatedly beat back the Viet Minh, inflicting very heavy losses at minor cost to their own. However, the French critically neglected to note the differences between the chosen field of battle at Dien Bien Phu compared to that at Nà Sản. First and foremost, at Nà Sản the French commanded most of the high ground (insert "Revenge of the Sith" joke here) with overwhelming artillery support. At Dien Bien Phu, however, they ceded control of much of the high ground around the valley to the Viet Minh, thinking that the VM wouldn't be able to transport heavy artillery to threaten their positions. As it is, Giap compared Dien Bien Phu to a "rice bowl," where this time his troops occupied the edge and the French the bottom. Second, Giap made a mistake in Nà Sản by committing his forces to reckless frontal attacks before being fully prepared. The French didn't think that he'd learn his lesson from that, but he did: at Dien Bien Phu, Giap spent months meticulously stockpiling ammunition and emplacing heavy artillery and antiaircraft guns around the French before making his move. Third, the aerial resupply lines at Nà Sản were never severed, despite Viet Minh antiaircraft fire. At Dien Bien Phu, the VM amassed antiaircraft batteries that quickly shut down the runway, and made it extremely difficult and costly for the French to reinforce and resupply it the same way they had at Nà Sản.