India, Aug. 7 -- Praggnanandhaa is wrapping up interviews after winning the Saint Louis Rapid & Blitz.

Within earshot is his older sister, Vaishali, the Rameshbabu family's other grandmaster and a contender in next year's Women's World Championship.

Usually, their mother, Nagalakshmi, accompanies Praggnanandhaa to tournaments. This time, with Nagalakshmi unable to travel, Vaishali arrived a week early ahead of the Cairns Cup, the strongest invitational women's tournament in the US, which begins in Saint Louis on August 8.

Asked how his sister's presence helped during the tournament in the American Midwest city, Praggnanandhaa grins and slips into familiar sibling banter. "Maybe we should kick her out before I answer."

Then comes the e...