5 ideas
The war moves through three phases: strategic defensive, where one survives and preserves forces; equilibrium or stalemate, where one builds strength and wears the enemy down; and general counter-offensive, where one fights to win. Each phase has its own ratio of guerrilla to mobile to positional warfare, and moving into the next phase too early risks losing everything already built.
The army's real base is a peasantry that has been politically organised and given a material stake, such as land reform and tax relief. That peasantry supplies recruits, intelligence, food and labour. Military capacity grows out of political work among the people, so a force that loses popular support loses its supply line, its eyes and its manpower together.
Local village militias, regional guerrilla units and main-force regular divisions are built as linked layers. The lower tiers harass the enemy, pin it down and feed trained fighters upward into the regular army. This lets a movement grow a conventional army step by step while guerrillas keep the enemy scattered across the countryside and unable to concentrate.
The French assumed artillery and supplies could not be moved through the mountains around Dien Bien Phu. The enemy's misjudgement of what mass human labour could move produced the siege that ended French rule in Indochina.
At Dien Bien Phu, Giáp called off a planned swift assault once he judged it could fail. He switched to a slow, methodical siege that tightened step by step, on the principle of striking only when success is sure. A campaign is judged by whether its decisive blow cannot fail, not by how fast it ends, so a commander must be willing to reverse a plan already under way.