Victory in last season's final for the Ospreys means they are likely to start as favourites once more, but the competition promises to be particularly fierce especially from the Scarlets who won the inaugural competition in 2005.
Dragons v Ospreys (Abertyillery Park)
Blues v Scarlets (Leckwith Stadium)
Both KO 7.15pm
Scarlets: G Griffiths; M Lemon, J Harries, D Etteridge, T James; D Newton, M Gibson; M Williams, R Guest, S Gardiner, I Davies, H Boot, D Zangouras, L Owen, A Bishop
Replacements: H Rees, R Lewis, R Williams, S Thomas, T Wilson, R Jones, C Jenkins, A Harries
Dragons: I Coombes (capt); G Dare, A Hughes, C Wannel, N Preece; D Ellis, D Jones; G Young, R Price, N Buck, M Allen, A Sweet, S Pailor, R Jenkins, L Bray
Replacements: S Maquire, A Borghese, D Reeks, C Filler, E Cracknell, J Burgess, B Sweet, W Browne