Under a scorching sun in Tokyo, octogenarian Katsuko Morita swings her mallet and whacks a ball through a small "gate." The diehard player of "gateball" is active almost every day, even when the mercury soars.

"Some of my friends in my generation tell me I must be crazy to go out playing gateball in this heat," said Morita, 81, at a practice session of the croquet-inspired game.

"When I'm playing the game, the heat doesn't bother me," she said, her face shaded by a wide-brimmed hat.