As Borussia Dortmund prepare for their tempestuous Matchday 12 derby against Ruhr district neighbours FC Schalke 04, bundesliga.com turns its spotlight on the German game's ultimate local power struggle.
The fixture is one of the most passionately contested in world football and it means more to each set of fans than any other fixture on the football calendar.
A Revierderby refers to the meeting of Dortmund and Schalke, who are based 32 kilometres away in Gelsenkirchen. A number of other professional teams hail from the wider Ruhr region, but they have to make do with the tag 'minor Ruhr derby' for their various head-to-heads.
Other than their proximity, there was no particular trigger for a rivalry which, if anything, has only intensified over the years for two sets of fans who basically like nothing more than to put one over on their neighbours.
While they might not necessarily like to admit it, Dortmund and Schalke actually have a lot in common: geography, obviously, but also roots in the coal and steel industries, as well as a striking similarity of their fan bases. Indeed, a predominantly working-class demographic defines the bulk of the support of both clubs. Dortmund's SIGNAL IDUNA PARK boasts a higher capacity than the VELTINS Arena, but Schalke's membership numbers comfortably outstrip those of their Schwarz-Gelben neighbours.
Die Knappen's pre-WWII dominance of Dortmund planted the seed for future Ruhr bragging rights, with the pendulum swinging from one side to the other ever since. In 1996/97, Schalke lifted the UEFA Cup, only to be trumped by Dortmund's UEFA Champions League success a week later.
Ten years down the line, Dortmund would have the last word, too, beating their great rivals on the penultimate Matchday of the 2006/07 season and effectively denying them a first Bundesliga title. In the spirit of true Schadenfreude, replica shirts commemorating the occasion were soon selling like hot cakes among the BVB faithful.
And just in case you needed any further convincing of what is at stake here, it may be worth noting the infamous response of dyed-in-the-wool Dortmund fan and former BVB player Kevin Großkreutz when asked what he would do if he had a son who chose to support Schalke. The answer? Adoption...