A novice breath technique that increases lung capacity. In the matsyasana pose, a novice monk lies on their back and pushes their chest up, taking on the aspect of a fish. The pose allows the monk to maintain their breath underwater, and even recover it by filtering air from the very water with their inner energy.
Being hit disrupts the pose, so asanas require that the monk hasn't been hit in the last few seconds.
Currently, the only way to improve this is by resting underwater. Don't drown!