According to tradition, when the Mari party calls at the door, you might just be able to avoid letting them in – as long as you’re a good enough poet and can hold a tune. Right now, standing on the threshold of the Maestag Corner House, Gwyn Evans breaks into song – a beautifully rich baritone that resounds through the little pub. The words are in Welsh, but a handy translation has been provided in a little printed leaflet I’ve been given: