Girl, 11, is youngest US chess master
For centuries chess has been a small game for big thinkers. Each player gets just 16 pieces to play on a board with 64 little squares.
The numbers start out simple, but the outcomes are virtually limitless. No surprise, then, that it takes most people years to get any good - let alone become what the chess world calls a "master".
Well, Carissa Yip has upended all those assumptions - for a start she's only 11 years old, and the word master doesn't really fit.
Jane O'Brien has Carissa's remarkable story.
Filmed by Ian Cartwright and Colm O'Molloy.Edited by Bill McKenna. Produced by Mat Morrison.
12 May 2015