Ian Chesterton-Marco Polo chess match

At a Gobi Desert camp in 1289, Marco Polo challenged Ian Chesterton to a game of chess. Tegana considered it a "fascinating game of strategy of war". (TV: "The Singing Sands") The match was won after 37 moves, with Marco quietly declaring his victory with "shah mat". Afterwards, the First Doctor accepted Marco's challenge. (PROSE: Marco Polo)