Washington made himself some friends in France. These friends sent a fleet to the Americas, where they caught the British navy by surprise. They then blocked off Yorktown by sea, while the American and French troops dug in around the British on land. They then laid siege with massive bombardments. After that, they sent a wave of troops to clean up, but the British ended up surrendering early. The victory was so large because of how many Brits were killed/captured. The war ended soon after, as the British had just lost a large amount of men AND the Americans had the French alongside them.
The Open Door Policy is a term in foreign affairs initially used to refer to the United States policy established in the late 19th century and the early 20th century, as enunciated in Secretary of State John Hay's Open Door Note, dated September 6, 1899 and dispatched to the major European powers.
