The Sgian Dubh (pronounced "skee(a)n doo", IPA /ski:n du:/, or lightly diphthongised /skiən/) is a ceremonial dagger (Gaelic sgian) worn as part of the modern Scottish Highland dress along with the kilt. It is worn tucked into the hose with only the pommel visible.
The name comes from the Gaelic meaning "black knife", where "black" may refer to the usual colour of the handle of the knife. It is also suggested that "black" means secret, or hidden, as in the word blackmail. This is based on the stories and theories surrounding the knife's origin.
The sgian dubh may have evolved from the sgian achlais, a dagger that could be concealed under the armpit. Used by the Scots of the 17th and 18th centuries, this knife was slightly larger than the average modern sgian dubh and was carried in the upper sleeve or lining of the body of the jacket.
Courtesy and etiquette would demand that when entering the home of a friend, any concealed weapons would be revealed. It follows that the sgian achlais would be removed from its hiding-place and displayed in the stocking top held securely by the garters.
The sgian dubh also resembles the small skinning knife that is part of the typical set of hunting knives. These sets contain a butchering knife with a 9-10 inch blade, and a skinner with a blade of about 4 inches. These knives usually had antler handles, as do many early sgian dubhs. The larger knife is likely the ancestor of the modern dirk.
The sgian dubh can be seen in portraits of kilted men of the mid 1800s. A portrait by Sir Henry Raeburn of Colonel Alasdair Ranaldson MacDonell of Glengarry hangs in the National Gallery of Scotland; it shows hanging from his belt on his right hand side a sheath holding nested hunting knives, and visible at the top of his right stocking what appears to be a nested set of two sgian dubhs. A similar sgian dubh is in the collection of The National Museum of Antiquities of Scotland.
The early blades varied in construction, some having a "clipped" or "drop" point, often found on the Bowie knife. The "spear-point" tip has now become universal. Scalloped filework on the back of the blade is common on all Scottish knives. A short blade of 3 to 3.5 inches is typical.
Since the modern wearer of the sgian dubh does not intend the blade for cutting food or self-defense, blades are now of a simple (but not unglamorous) construction. These are typically stamped from brass and nickel-plated. The basic handles are plastic fitted with plated castings with synthetic decorative stones. Some are not even knives at all, but a plastic handle and sheath cast as one piece. Some blades however, are luxurious and expensive art pieces, made from solid silver or Damascus steel. Blades can be etched with family crests, Masonic or regimental symbols.
The scabbards are reinforced with wood and fitted with decorative ends, and can also have crests and symbols. While this makes for more popular and expensive knives, the sheath is hidden from view in the stocking while the sgian dubh is worn.
As Gaelic words often pose problems for English speakers, many erroneous spellings are found in the literature surrounding the kilt and Highland dress, mostly involving misplacing the h, imitating the pronunciation or confusing sgian with the place-name Skene:
- skein dubh
- sgian dhub
- skene du
- skean dhu
- skhian dubh