stance with legs in an L-shape, with one leg bent in front and other extended behind (martial arts, traditional theater)
剣道では相手に半身で構える。
In kendo, you face your opponent in a half-stance.
半身の姿勢を取ることで身を守りやすくなる。
Taking a half-stance makes it easier to protect yourself.
師範は半身で構えながら弟子に技を説明した。
The master explained the technique to his disciple while holding a half-stance.