A puukko () is a small traditional Finnish general purpose belt knife with a single curved cutting edge, solid hidden tang and, usually, a flat spine. Military models of puukko were popular in the Russian criminal underworld under the name "Finnish knife" or finka since the 20th century. The modified version were among the models on which the Soviet military knife NR-40 was based and which was informally called "finka". Design The basic components of a puukko are a handle and a blade along with a sheath, which can usually be attached to a belt but sometimes to a shirt or coat button. The blade is usually short, typically no longer than the handle and can often be less than 4" (100 mm). The flat grind makes the puukko a natural choice for slicing, cutting and whittling, and the flat spine allows the user to use a thumb or the other hand to bring more force to bear to the task at hand. Puukkos are most often used as carving tools for decorative and fire-making purposes and to clean fishers' and hunters' catches. Some puukko designs have a slightly upwards or downwards curved point, depending on what purpose the knife has. A hunting puukko's tip is often curved downwards to make skinning and opening the animal easier and less messy. Fishermen's puukkos sometimes have a small dovetail on point to ease scraping off the innards of a fish. Most puukkos have a slight shoulder but no ricasso (section of unsharpened blade nearest the handle) because the point where the edge ends and the handle begins is also the point where most power can be applied. A puukko typically has no finger guard, since it is primarily considered a cutting tool, not a stabbing weapon. Where the knife and the hand are expected to get wet, such as when the puukko is intended for gutting fish or game, a form of guard is carved into the handle. The traditional length of the puukko blade is the same as one's palm width, usually 90–120 mm. Carvers, huntsmen and leatherworkers favour shorter blades; woodworkers, carpenters and constructors longer. The blade of the historical väkipuukko may be up to 500 mm. The väkipuukko more closely resembles a seax or short sword than true puukko, although it has given the form for the leuku of the sámi people. Both factory-forged and hand-forged blades may be