A precocious talent who stunned Garry Kasparov and Viswanathan Anand as a teenager, the former World No. 4 was on the verge of quitting chess because of a lack of motivation. But the 2019 World Cup triumph, in which he beat current World champion Ding Liren, kept him in the game. He talks about his life, his career and world chess in this freewheeling chat