The uilleann pipes (from Irish uille, 'elbow') are inflated by a bellows under the right arm rather than by mouth. The player sits, presses the chanter's foot against a leather pad on the knee to stop the sound completely, and can chord the drones using three keyed regulator pipes with the wrist. Where the Scottish Highland pipe produces one continuous drone-plus-melody line, the uilleann pipes can start and stop notes cleanly, harmonise underneath the melody, and reach a full two octaves. That mechanical freedom is why the pipe developed the intricate ornament vocabulary — cuts, rolls, and cranns — that defines Irish trad more than any other instrument does.

The uilleann pipes evolved in the early eighteenth century, drawing on continental European bellows-pipes (musette, Northumbrian smallpipe) but rebuilt for indoor drawing-room playing. Through the nineteenth century they were the 'gentleman piper's' instrument, played in country houses as well as in cottages. By the mid-twentieth century the tradition had almost died out — full sets were expensive, makers were scarce, players were an ageing handful. The 1968 founding of Na Píobairí Uilleann (the Uilleann Pipers' Society) reversed the decline by archiving recordings of the surviving masters (Willie Clancy, Leo Rowsome, Séamus Ennis) and training new players. A full concert set now takes years to build and carries a ten-year waiting list.

First, listen for the regulators. The player's wrist occasionally taps the chord keys, and short harmonic stabs appear underneath the melody. That is the sound that no other bagpipe in the world makes. Second, notice the range — the chanter reaches two full octaves, so the melodies leap much further than a Highland pipe tune can. Liam O'Flynn's 'The Given Note' (1995), inspired by a Seamus Heaney poem, is the finest slow-air recording: an unmetered melody drifting above the drone. Paddy Keenan on the reels is the opposite extreme, moving at a speed that changed what pipers thought possible.

Start with Liam O'Flynn's 'The Given Note' (1995) for the slow-air side and one of the most poised recordings any Irish musician has made. Then Paddy Keenan's self-titled solo album (1975), captured just before he joined The Bothy Band, for pure speed. For the tradition-preservation strand, 'The Pipering of Willie Clancy' (posthumous compilation) is the reference document. Play loud on a good speaker at night; the drones need physical air to breathe.

UNESCO added uilleann piping to its Intangible Cultural Heritage list in 2017. Willie Clancy earned his living as a carpenter and played only at weekends in his home village of Miltown Malbay, Co. Clare. Since his death in 1973, the Willie Clancy Summer School has run every July, drawing thousands of students from all over the world for a week of workshops on every traditional instrument — the closest thing the Irish tradition has to a mothership. The pipes' most globally famous appearance is on the Titanic (1997) soundtrack, where Liam O'Flynn and Paddy Moloney's playing on the steerage-class scene sold millions of copies to audiences who had never heard the instrument before.