Samurai may be known as a man's pursuit, but feudal Japan produced a number of legendary female warriors who took to the battlefield with a sword that still holds a high cultural position today.

The image of the katana sword continues to draw interest from women, and enthusiasts in Tokyo are now learning ancient fighting techniques adapted into an energetic sports-like activity.

Katana exercise began life as a workout intended for men seven years ago, combining ancient virtues and practices in a gym session. It found surprising popularity among women, and as a result its inventor decided to limit apprenticeships to females only.