Some say that the south Wales derby is one of the fiercest rivalries in British football.
After a five year wait, east travels west in a crucial match in the Championship this Sunday.
The first match between Cardiff and Swansea was played back in 1912. Since then, the two teams have played each other 106 times.
Cardiff have won 44, Swansea have won 35, and 27 have been draws.
So history favours the men in blue, but Swansea's better start to the season means they are four points ahead of Cardiff - sitting 9th and 13th respectively.
Earlier this week, I sat down with Swans boss Steve Cooper. He's been in the job for four months, and this will be his first ever derby in a senior role.
"Everything is a first for me at the moment", he tells me.
"There is different challenges around every single game, and we try and address them. And obviously the one on Sunday is obviously a derby, representation of a city, of a community, against your local rivals. And we're very aware of that.
"Is it a bit different? Of course it is. There's going to be an amazing atmosphere here, it's going to be a sell out, and the fans are really going to be behind us."
Meanwhile, Neil Warnock has experienced more than his fair share of football derbies during 40-year managerial career.
“They’re all fantastic these derbies, you look at the fixtures as soon as they come out, you know wherever you are and whatever derby it is.
"Two passionate crowds, all be having digs at each other I’m sure in the build up, and it’s an important game.
"It would have been nice to have this derby in the Premier League, but we’re both where we are and both desperately trying to get back up there."
Watch Beth Fisher's full report here