H. J. Murray wrote a book on the history of this activity and included several Arabic documents pertaining to it called “mikhariq” (“mee-CAR-ihk”). This is the first of three activities that was the subject of a book commissioned by Alfonso X of Castile that includes its “astronomical” variety. (-5[1])A “great” variation of this activity was legendarily developed by Tamerlane. (15[1])A discovery (15[2])on the Isle of (*) Lewis (10[2])yielded (10[2])a hoard (10[1])of (10[2])items (10[4])used for this (10[1])activity (10[3])made mostly from walrus (10[1])ivory. (10[3])A treatise on this (10[1]-5[1])activity by the Spanish priest Ruy Lopez (10[2])introduced (10[2])a namesake (10[2])strategy (10[1])for this activity. (10[1])This activity evolved from a similar one in India called chaturanga, (10[1])which also used an eight-by-eight board. For 10 points, name this board game where players seek to win through checkmate. ■END■ (10[1])