IN THE TRAINING ROOM THE sound of the wooden swords cracking together echoed sharply. Lieutenant Patel worked Loi hard, and sweat poured off her while they moved around the room. She threw her sword up to deflect a blow he aimed at her head, his sword slamming into hers and she wavered under the weight.

'Yield to it!' Patel bellowed. 'Allow your attacker to over extend, it reveals their weakness.'

Loi nodded and they backed apart to try again. This time when his sword ...