The earliest form of the game now known as chess dates back to 6th century India. The game was called chaturanga (or catur) and was played on an 8x8 grid with pieces that shared similarities with those used in modern chess. Some key differences included more limited rules for moving counselors (called queens today) and elephants (called bishops today). Some accounts also mention that chaturanga could be won when one player removed all of their opponent’s pieces besides the king. Over time, chaturanga spread to Persia, where it became known as chatrang by the tenth or eleventh century. The game also spread into the Arab world, China, Japan, and Southeast Asia. The Arab version entered Europe during the 12th and 13th centuries and was adopted by European nobility. It gained widespread popularity in Europe by the 19th century and the first international chess tournament was held in London in 1851. A number of important chess matches took place in subsequent years, including a historic match between Boris Spassky and Bobby Fischer in 1972 and a 1997 match between IBM’s Deep Blue supercomputer and chess champion Garry Kasparov. The current chess champion is Magnus Carlsen.