Neck
Ryu sat in his courtyard without a care having entered a deep state of meditation. In fact, he had even swallowed two Silver Vein Petals, bringing his state to the Breath of World stage.
To others, a training session like that was only useful in the moment, but to Ryu who had [Focus], the Spirit Seeking Lilies, and the Origin Flame, he could return to that moment in even greater detail than he had when he lived it the first time.
Every single instant of moment, every mistake, every one of Matheus' actions and inactions, were replayed in his mind to the utmost perfection. In the state of Breath of World, it was as though Ryu's breathing was in sync with the very ground he sat upon. The grass moved with the beating of his heart, the soils vibrated with the motion of his qi, and the skies above seemed to shine light only for his usage.