The Dayan Panshi is the sixth 3x3 cube in the Dayan series. Panshi means solid rock in Chinese. In other words it means that this cube is as solid as a rock and won't slip on you that easily.
The Panshi is similar and different with the zhanchi (Day A's 5th cube). A significant difference is that the Pans hi has a much smaller core 14mm rather than the 18.