The Röstigraben, (German pronunciation: [ˈrøːstiˌɡraːbən]), literally ‘Rösti ditch’, also transcribed Röschtigraben in order to reflect the Swiss German pronunciation [ˈrøːʃtiˌɡrabə], is a humorous term describing the dividing line between the German-speaking and the French-speaking Romands parts of Switzerland with their respecitve cultural differences. The first part of the term is derived from the Swiss-German name for hashed potatoes, Rösti, which originated in the Canton of Bern and is considered typically of German cuisine.[1][2][3]
"Graben" has both the concrete and abstract meaning of rift, with the Saane river valley in the bilingual Canton of Fribourg separating the linguistic areas. The Swiss-French use a similar expression: barrière de Rös(ch)ti, literally "Rösti barrier" or Rideau de rös(ch)ti ("Rösti curtain"). Just like Röstigraben it has become a familiar facetious expression used whenever differences arise, e.g. the different voting results.
In recent years, however, the differences in politics seem to be weakening as the urban areas of German-speaking Switzerland vote similarly to French-speaking Western Switzerland.