Ubiquitous in rural Japan, the Japanese nata is serious multi-purpose green woodworking tool. Like billhooks everywhere they are produced in a bewildering variety of shapes, but these were recommended to us as being the most suitable for making things (as opposed to agricultural and horticultural uses). Like many green woodworking tools they are comparatively ineffective on dry hardwoods but will sail through fresh green ash or sycamore beautifully.
The 135mm nata has a longer handle and a heavy 9mm thick laminated blade so it's a little closer to an axe in feel and function. Nata will easily take a shaving sharp edge (and are intended to be kept sharp), but the thick heavy blade and wide, flat primary bevels can also be used for splitting and light chopping.
Flat bevels are important for finer work because they allow that edge to engage at very shallow angles - ideal for preparing green wood blanks for carving or turning, hedge laying, hurdle making, pointing stakes, feathering and other tasks that call for a shallow glancing cut.The cutting edge is slightly crowned along its length, focussing the energy of a chopping blow to give more bite, just as the curved edge of a felling axe does.
You can easily limb, or even fell, a small tree with a nata. The flared handle provides a comfortable grip and prevents it from slipping out of your hand when chopping.