Tune of the month: Da Slockit Light

If last month's tune was the tradition at full sail, this month's is the tradition at dusk. Da Slockit Light is a slow air written by Tom Anderson in 1969, and in half a century it has travelled further than perhaps any other Shetland tune — you'll hear it in sessions from Galway to Seattle, often by players who have no idea where it comes from.

"Slockit" is Shetland dialect for a light that has gone out. Anderson wrote the tune driving down through the North Mainland at night, looking at the scattered lights of Eshaness and thinking about how many crofts had gone dark in his lifetime — emigration, clearance by economics if not by edict. The tune is an elegy for lit windows.

Playing it. The notes are not difficult; the discipline is. The whole art of the tune is in not rushing — in letting each phrase breathe out fully before the next begins.

• Play it in D, as written. Resist the urge to ornament heavily; one considered slide is worth five cuts.
• The long notes should swell and fade — think of the bow as breath.
• The second part climbs, and the temptation is to get louder and faster together. Get louder if you like, but hold the tempo like an anchor.
• It's a tune that suits company: fiddles in unison, an octave below on a low fiddle or box drone underneath.

We finish most Tuesday sessions with it when the night has been a good one. There is no better test of a room than whether it goes quiet for the last eight bars.