These knives are the Lua Shan Dao/ Midori Yama, or Green Mountain knife line. These are all no frills, well made knives with a focus on what matters most, thin grinds, excellent heat treats and balanced design.
All the blades are hand forged before being ground, and heat treated with a kiln and quenched in proper quenching oil. Most of the blades are a 1075/1010 san mai, and many feature a very interesting design thats not very common outside of Western china, a flared spine. The blades hard steel core only extends about an inch into the blade, so the spine and handle are very soft iron, and as the blades are incredibly thinly ground, they would be liable to flex slightly, not something you want for the smooth chopping and slicing action Chinese knives are designed for. So the last roughly 1/4 inch of the spine is flared outward, providing both rigidity as well as a lightly weight that helps the knives have a wonderful motion in chopping.