Tuesday evening will see the first meaningful south Wales derby for nine years when Swansea City host Cardiff City in the Carling Cup.
It is a match eagerly anticipated by both sides' supporters in what in the past has been described as one of the most fierce rivalries in British football.
Whoever wins will have the bragging rights until the two sides meet again in the league at the end of November.
But the biggest winners will be the supporters if the night is trouble-free, given the history between the two sides.
Perhaps the most famous clash, which Cardiff fans are often reminded of by their neighbours, was in September 1988.
SWANSEA v CARDIFF FACTS
The two sides have played each other 57 times since the war (excluding the Welsh Cup and FAW Premier Cup)
Cardiff have won 19 times
Swansea have won 23 times
The game has ended in a draw on 15 occasions
Cardiff have scored 68 goals while Swansea have found the net 74 times
The last league meeting, in April 1999, finished 0-0
Cardiff won the last League Cup meeting 2-1 on aggregate in September 1988
Swansea won the last FA Cup meeting 2-1 in November 1991
The last match between the two was Cardiff's 1-0 FAW Premier Cup win in 2002
Swansea's Roger Freestone has played in the most derbies (19) - two more than Cardiff's Alan Harrington
It followed Cardiff's League Cup first round second leg tie at Swansea's Vetch Field where Cardiff won 2-0 (2-1 on aggregate).
The South Wales Evening Post reported the next day that around 30 Cardiff supporters were chased into the sea, a short distance from the ground.
Since then, Bluebirds fans have been reminded of the event with a "swim away" chant from their rivals.
But arguably the ugliest scenes came in December 1993 at Cardiff's Ninian Park.
The Bluebirds' 1-0 win was overshadowed by trouble in the main stand when hooligans ripped out seats and hurled them at each other, sparked by the Swansea element.
It led to away fans being banned from games for some years, the first fixture to do that in British football.
They were allowed to return when "bubble matches" (where fans are escorted to the games by police on official supporters' buses only) were introduced.
The last significant match was played in the league in 1999, the season when Cardiff won promotion from the old Division Three.
Fans spilled on to the pitch during the trouble at Ninian Park in 1993
Since then, the two sides have only played each other in 2002 when Cardiff won the FAW Premier Cup at Ninian Park.
Both clubs have seen dramatic changes on and off the pitch over the last nine years, but now they are on the road to success in the second tier of English football.
And since the last meeting, relations between the two clubs have vastly improved on several levels.
The most recent was earlier this month when the Swansea City Supporters' Trust helped Cardiff fans set up their equivalent.
Both are hoping for a night of peace.
Paul Corkrey, acting chairman of the Cardiff City Trust said: "We are all aware of the emotion and intensity that surrounds this traditional derby match, and without that fervour the game would inevitably be a lot poorer.
Interviews: Former players Alan Curtis and Andy Legg on the derby
"However, it is the responsibility of us all, as supporters of each club, to ensure that such passion does not extend beyond the boundaries of acceptable behaviour."
And Phil Sumbler, chairman of the Swans Trust added: "There is no doubt that the eyes of the media will be firmly focused on us for our first meeting in nine years.
"Let it be remembered as an occasion that displays the raw passion and sporting rivalry that exists in South Wales in its true light, and not for the wrong reasons."
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