The United States and Soviet Union began a race to develop the first and most capable fifth generation stealth fighters in the late 1970s. The Cold War’s end, however, was followed by both a near total collapse of Russian efforts and major cuts and delays to American programs. This provided an opening for a rising and fast modernising Chinese defence industry to kick off its own ambitious program to produce a world leading fighter jet with next generation capabilities. Once unveiled, the program came to be seen as a herald of China’s rising status as a leading player in high tech and major world power. Development of the Chengdu J-20 began in the 1990s and has since consistently far exceeded expectations in both its performance and its development timeline. The fighter made its first flight in 2011 and began deliveries to the People's Liberation Army Air Force in 2016 – a small fraction of the time its American and Russian rivals would take. Today it is the world’s second most numerous stealth fighter, outnumbered only by America’s much smaller Lockheed Martin F-35 Lightning II, with the two rivals seeing their first of many likely encounters confirmed in March 2022\\. As the J-20’s capabilities have rapidly improved and the rate of production has significantly grown, it has very conspicuously played a growing role in patrolling major hotspots in East Asia from Korea and the East China Sea to the Taiwan Strait and disputed South China Sea. The J-20 program’s success has been the most potent symbol of China’s ascent from a minor player in combat aviation during the Cold War, to the United States’ only peer level competitor today. It has also set China on a course of pursuing multiple other fighter development efforts – including a close competition with America to field the first and most capable sixth generation fighter in the 2030s. The J-20 thus marks a major landmark not only in Chinese aviation history, but also more broadly in the evolving balance of power between East and West as the country’s technological and economic ascents allow it to successfully pursue highly ambitious weapons programs. This book takes the J-20’s story far back to the formation of the People’s Liberation Army Air Force and its trial by fire in the Korean War, tracing the rationale for developing a top end air superiority fighter. It also compares its performance with rival fifth generation fighter programs in other countries and looks ahead to what the future may hold in this new arms race.