Which 11-point Scrabble word is the most commonly used in tournaments?

Although it's most commonly spelled CHI in standard usage, the variant form QI is the single most-played word in SCRABBLE tournaments, according to game records of the North American SCRABBLE Players Association (NASPA).

According to traditional Chinese medicine and philosophy, qi—also known as chi—is the vital life force that flows through our body. This word is commonly played when someone has a pesky Q as it only requires an open I.