This article explores the US-Japan relationship and why the US is protecting Japan. It discusses the history of the two countries, beginning with Commodore Perry forcing Japan to open its ports to foreign trade in the mid-1800s and ending with the San Francisco Peace Treaty in 1951 which officially ended World War II for Japan and established a new relationship between them. The Mutual Defense Treaty of 1960 committed both countries to defend each other in case of an attack from another country or group of countries. The alliance provides economic, geopolitical, and humanitarian benefits for both countries, such as increased trade, investments by American companies in Japan's economy, protection against potential aggression from other powers such as China or North Korea, and promoting peace & stability while helping those who need help most.