Here's what someone else said about puukos on this forum several years ago (worth repeating):
‘Puukko’ is a Finnish term. It’s a derivative of ‘puu’ which means wood. A puukko is, first and foremost, a wood carving tool (we have a special term for that, ‘vuoleminen’, the root verb being ‘vuolla’, which comes close to whittling or wood carving, but denotes specifically the use of the blade for push-cuts, not slicing or slashing). Other ‘necessary’ uses of a puukko have to do with fishing and hunting, i.e., scaling, skinning, filleting, and other such tasks in preparing fish and game. Skilled users do about everything with a puukko, though. Once it was thought that a boy really doesn’t need other purchased toys; after he gets a puukko, he’ll make everything else with it. This is no joke! In the 50’s, schoolboys were (at some places) forbidden to use the puukko during wood-carving lessons, because they wouldn’t otherwise learn to use other tools, like planes, saws and chisels. Now the situation is, of course, quite different. Many Finns do not learn to use the puukko properly, though some kind of renaissance may be discernable here (there’s even a special ‘vuolukirja’, whittling book, by Joel Nokelainen 1996, but I think, only in Finnish). The puukko has developed to remarkable functional simplicity during generations of hard, straightforward use by ordinary people. It is a compromise, a multi-tool, if you like, with nothing inessential. That explains some of its characteristic features. The blade, for instance, is typically only a hand width in length, or a bit less. A longer blade would hamper its performance in whittling, etc. control is better with a shorter one (for fine work, such as countersinking a hole, the puukko is grasped by the blade and the thumb may be used as a ‘backstop’). But because it is not a ‘pure’ wood carving tool, too short won’t do. Similar explanations could be given for the relatively pointy point (remember the hole?), the (usually) straight back (with absolutely no false-edge or swedge), the wedgelike grind, the relatively thin blade, the smooth guardless handle (often called the head), made traditionally of wood, mostly birch, or of birch bark, etc. There are, of course, exceptions, and specialization is taking place here, too. But most of the recent developments in puukko may be more market-driven than purely function. For instance, the recent proliferation of finger-guards comes solely from legislative (consumer protective) demands of USA. A traditional puukko does not need them, as it is not meant for stabbing (though they were used for that too by the ‘puukkojunkkarit’, a group of Finnish outlaws at the Kauhava region quite a few decades ago). The carry system, in Finnish ‘tuppi’, is traditionally great. It’s not a quick-draw or concealment item or anything like that, but protects the puukko (and its owner) well, keeps it securely in place, does not hamper sitting, etc., and is aesthetically pleasing (the puukko is often called ‘tuppiroska’, sheath-litter, as it were and that could, I guess, reflect the high esteem that traditional makers have had for the sheath). But everyone does not know anymore how to make a proper tuppi (or does not have the time/financial means for that). About the grind. Not every puukko has a high saber grind (or ‘wide flat Scandinavian grind’, as somebody said), and not every puukko lacks a secondary bevel, though typically they do. Sharpening the whole flat sides every time would wear the blade down quickly (this actually happens – there are many puukkos around that resemble only faintly what they were as new), though for ‘vuoleminen’ you do need a very acute angle (about 15/30 degrees). In addition, there are (new) puukkos with a secondary grind as well as some with a convex grind (notably, the Lapinleuku, the traditional tool of reindeer-owners). About the thickness, yes, puukko blades tend to be relatively thin (and not very wide, either, and they do not have a full tang, which I have often grumbled myself). This relates again to its primary functions. It’s not convenient to ‘vuolla’ or to fillet with a thick blade, and you do not, typically, chop or pry with a puukko (for chopping we use the axe and for prying the other guy’s tools).
