Which Belgian village was the main focus of the Prussian flank attack?

Plancenoit was the Belgian village that became the main focus of the Prussian flank attack at Waterloo.

The village lay southeast of Wellington’s position and directly threatened the French army’s right flank and line of retreat. Prussian IV Corps under Friedrich Wilhelm von Bülow reached the battlefield first in strength and aimed to seize Plancenoit as a springboard into Napoleon’s rear. Fighting there began in the late afternoon and soon became one of the battle’s most intense local actions.

French troops under Georges Mouton, Count de Lobau, defended the village. Napoleon repeatedly reinforced them with the Young Guard and later elements of the Old Guard, because losing Plancenoit would expose the road toward Charleroi and threaten the French withdrawal. The village changed hands several times before the Prussians captured it decisively during the French collapse.

Ohain was on the allied left, Genappe lay farther south along the retreat route, and Waterloo was the nearby settlement that gave the battle its familiar name. None was the principal target of the Prussian flank assault.