Uilleann pipes are the characteristic national bagpipe of Ireland. The uilleann pipes bag is inflated by means of a small set of bellows strapped around the waist and the right arm. Found in other European bagpipes (ex. Northumbrian pipes, Scottish smallpipes), the bellows not only relieves the player from the effort needed to blow into a bag to maintain pressure, they also allow relatively dry air to power the reeds, reducing the adverse affects of moisture on tuning and longevity. Some pipers can smoke, converse, or sing while playing as well.

The Uilleann pipes are distinguished from many other forms of bagpipes by their sweet tone and wide range of notes — the chanter has a range of two full octaves, including sharps and flats — together with the unique blend of chanter, drones, and "regulators." The regulators are equipped with closed keys which can be opened by the piper's wrist action enabling the piper to play simple chords, giving a rhythmic and harmonic accompaniment as needed. There are also many ornaments based on multiple or single grace notes. The chanter can also be played staccato by resting the bottom of the chanter on the piper's knee to close off the bottom hole and then open and close only the tone holes required. If one tone hole is closed before the next one opened, a staccato effect can be created because the sound stops completely when no air can escape at all.

The Uilleann pipes have a different harmonic structure, sounding sweeter and quieter than many other bagpipes, such as the Great Irish Warpipes or Great Highland Bagpipes. The Uilleann pipes are usually played indoors, and are almost always played sitting down.

History

The first bagpipes to be well-attested to for Ireland were similar, if not identical, to the Highland pipes that are now played in Scotland. These would be the ancient Irish pipes, which were given the name of "Irish Warpipes" or "Great Irish Warpipes" in the 1920s. In Irish, this instrument was called the píob mhór ("great pipes").

The Uilleann or union pipes developed around the beginning of the 18th century, the history of which is here depicted in prints of carvings and pictures from contemporary sources. At about the same time the Northumbrian smallpipe was evolving into its modern form, early in the 18th century; a tutor of the 1750s calls this early form of the Uilleann pipes the "Pastoral or New bagpipe." The Pastoral pipes were bellows blown and played in either a seated or standing position. The conical bored chanter was played "open," that is, legato, unlike the Uilleann pipes, which can also be played "closed," that is, staccato. The early Pastoral pipes had two drones, and later examples had one (or rarely, two) regulator(s). More information on the evolution of the pipes will be given below. The Uilleann Pipes may have developed with ideas on the instrument being traded back-and-forth between Ireland and Britain, around the 18th and early 19th century.

The earliest surviving sets of uilleann pipes date from the second half of the 18th century but it must be said that datings are not definitive. Only recently has scientific attention begun to be paid to the instrument and problems relating to various stages of its development have yet to be resolved.