Chess is a board game played between two players on a square board consisting of 64 squares, arranged in an 8x8 grid. The game is believed to have originated in northern India in the 6th century, where it was known as chaturanga. From there, it spread to Persia and later to the Arab world. The modern rules of chess were standardized in the 15th century in southern Europe, particularly in Italy and Spain. The game quickly became popular among the nobility and royalty, and it was played in courts throughout Europe. In the 19th century, the game was transformed by the emergence of chess theory and the development of new openings and strategies. The first chess tournaments were organized in the mid-19th century, and the first international tournament was held in London in 1851. In the 20th century, chess became an international phenomenon, with players from around the world competing at the highest level. The World Chess Championship has been held regularly since 1886, and many of the greatest players in history have held the title, including Wilhelm Steinitz, Emanuel Lasker, José Capablanca, Alexander Alekhine, Mikhail Botvinnik, Bobby Fischer, Anatoly Karpov, Garry Kasparov, Vishy Anand, and Magnus Carlsen. Today, chess is played by millions of people around the world, both recreationally and competitively. It is recognized as a sport by the International Olympic Committee and has its own international federation, FIDE (Fédération Internationale des Échecs). Chess is also used as a tool for education, as it has been shown to improve cognitive abilities such as memory, problem-solving, and creativity.