While I personally think the curvy, V-shaped Gua sha tools are easier for beginners since it’s more intuitive (you just hug it against your face), rectangular ones like Cosmic Stone can be designed to offer up to four different modalities for each side. Cosmic Stone’s long side has a wavy edge
for smooth sculpting of the neck, cheeks, forehead or under-eye, a shorter, softly curved edge for smaller areas, a straight comb edge for a massage-like feel, and lastly a V-shaped arc short edge that can be used anywhere from brows, cheekbones, along the jaw, or even the spine. (As someone with scoliosis, I cannot recommend this more for tight upper back muscles.)
for smooth sculpting of the neck, cheeks, forehead or under-eye, a shorter, softly curved edge for smaller areas, a straight comb edge for a massage-like feel, and lastly a V-shaped arc short edge that can be used anywhere from brows, cheekbones, along the jaw, or even the spine. (As someone with scoliosis, I cannot recommend this more for tight upper back muscles.)
