Son ar chistr ("The song of the cider" in the Breton language, "Ev Chistr ’ta Laou!" originally) is a traditional song of Brittany, whose words in Breton were written in 1929 by two Morbihan teenagers Jean Bernard and Jean-Marie Prima. The melody became known by the interpretation of the famous Breton singer Alan Stivell in the 1970s and in 1977 by the Dutch band Bots under the name "Zeven dagen lang".