The earliest precursor of modern chess is a game called chaturanga, which flourished in India by the 6th century, and is the earliest known game to have two essential features found in all later chess variations different pieces having different powers (which was not the case with checkers and go), and victory depending on the fate of one piece, the king of modern chess.[9] Other game pieces (speculatively called "chess pieces") uncovered in archaeological findings are considered as coming from other, distantly related, board games, which may have had boards of 100 squares or more.[9] Findings in the Mohenjo-daro and Harappa (26001500 BCE) sites of the Indus Valley Civilization show the prevalence of a board game that resembles chess.[16] Chess was designed for an ashtapada (Sanskrit for "having eight feet", i.e. an 8x8 squared board), which may have been used earlier for a backgammon-type race game (perhaps related to a dice-driven race game still played in south India where the track starts at the middle of a side and spirals in to the center).[17] Ashtapada, the uncheckered 8?8 board served as the main board for playing Chaturanga.[18] Other Indian boards included the 10?10 Dasapada and the 9?9 Saturankam.[18] Traditional Indian chessboards often have X markings on some or all of squares a1 a4 a5 a8 d1 d4 d5 d8 e1 e4 e5 e8 h1 h4 h5 h8: these may have been "safe squares" where capturing was not allowed in a dice-driven backgammon-type race g me played on the ashtapada before chess was invented.[17] The Cox-Forbes theory, started in the late 19th century, mainly from the works of Captain Hiram Cox and Duncan Forbes, proposed that the four-handed game chaturaji was the original form of chaturanga.[19] Other scholars dispute this and say that the two-handed form was the first.[20] In Sanskrit, "chaturanga" (---?) literally means "having four limbs (or parts)" and in epic poetry often means "army" (the four parts are elephants, chariots, horsemen, foot soldiers).[7] The name came from a battle formation mentioned in the Indian epic Mahabharata.[9] The game Chaturanga was a battle simulation game[7] which rendered Indian military strategy of the time.[21] Some people formerly played chess using a die to decide which piece to move. There was an unproven theory that chess started as this dice-chess and that the gambling and dice aspects of the game were removed because of Hindu religious objections.[22] Scholars in areas to which the game subsequently spread, for example the Arab Abu al-Hasan 'Ali al-Mas'udi, detailed the Indian use of chess as a tool for military strategy, mathematics, gambling and even its vague association with astronomy.[23] Mas'udi notes that ivory in India was chiefly used for the production of chess and backgammon pieces, and asserts that the game was introduced to Persia from India, along with the book Kelileh va Demneh, during the reign of emperor Nushirwan.