POOL A - ULSTER v MUNSTER (at Ravenhill, Belfast, 7.35pm).
Munster, the only unbeaten side in Pool A travel to Belfast hoping to repeat last season's 15 - 9 Celtic League semi-final victory over the 1999 Heineken Cup champions.
Both sides are missing their Irish international players who are preparing for Saturday's World Cup qualifier against Georgia in Dublin.
Ulster will be captained by Irish international lock Jeremy Davidson in the absence of the injured Andy Ward, and after a fine performance against Neath last weekend, Adam Larkin continues at fly half.
Mick Galway skippers Munster due to an injury to Jim Williams. Williams has a damaged knee, and coach Alan Gaffney is wary of risking the influential flanker.
"Jim's injury is not too serious, a little swelling on the knee, but at this stage of the season we're not prepared to take chances," said Gaffney.
"It is never easy to get anything out of Ravenhill and we can expect a capacity crowd to get right behind Ulster. It's a game they know they must win. So all in all, I'd say we're right up against it."
Ulster: B Cunningham; J Topping, R Constable, J Bell, T Howe; A Larklin, N Doak; J Fitzpatrick, M Sexton, R Kempson, M Blair, J Davidson (capt), W Brosnihan, T McWhirter, N McMillan. Replacements: S Best, P Shields, P Johns, N Best, K Campbell, S Stewart, S Young.
Munster: J Staunton; D Crotty, M Mullins, J Holland, M Lawlor; K Keane, M Prendergast; M Horan, F Sheahan, R Laffan, M Galwey (capt), M O'Driscoll, D O'Callaghan, E Halvey, D Leamy. Replacements: J Blaney/J Fogarty, S Kerr, T Hogan, C McMahon, D Malone, C Mahony, C Huppert.
Referee: P Adams (Wales).
Out - Ulster: A Ward (ankle), J Williams (knee), S Coulter.
Munster: D Wallace, A Horgan, P O'Connell, M Cahill.
POOL A - NEATH v EBBW VALE (at the Gnoll, 6.45pm).
Despite falling to Ulster last weekend, Neath are in a rich vein of form, and with three wins in this years Celtic League, the Welsh All Blacks will start this match as hot favourites.
But Neath coach Lyn Jones is keeping his feet firmly on the ground
"Over the last four years we have had some great high scoring matches against them, and the moment you take a win for granted you will lose."
Neath won both meetings in the Welsh/Scottish League, but Vale were victorious in the Principality Cup last season. The Steelmen have only won twice in Welsh League games at the Gnoll, 16-15 in 1996/97 and 22-20 in 1998/99.
Ebbw Vale have recorded just one victory in the Celtic League this season, against Caerphilly.
Peter Sidoli, younger brother of Pontypridd lock Robert, is impressing after sitting most of last season out with injury.
Coach Mike Ruddock had words of support for the young forward. "Peter [Sidoli] made things happen on Saturday," he said
Ruddock has included flanker Paul Williams at openside flanker with Tyron Morris suffering from a neck injury. Willaims recent memories of the Gnoll include a sending off last season, so he will be keen to make up for that this weekend.
Neath: (from) Backs - G Morris, J Story, D Tieuti, A Bateman, S Williams, L Jarvis, S Marsden, S Connor, A Moore, P Horgan. Forwards - D Jones, A Jones, A Millward, S Jones, B Williams, G Llewellyn (capt), A Newman, H Jenkins, S Martin, A Mocelutu, S Tandy, N Bonner-Evans.
Ebbw Vale: R Davies; N Wakely, M Ridley, E Binham, R Shorney; M Meenan, B Shelbourne; P Jones, J Evans, A Black (capt), P Sidoli, N Edwards, K Tuipulotu, W Thomas, P Williams, Replacements: C Gay, K Crawford, O Booyse, R Williams, A Bevan, S Mitchell, A Takarangi.
Referee: G Davis (Scotland).
Out - Neath: B Sinkinson (knee), J Leyshon (shoulder), A Matthews (knee).Ebbw Vale: C Billen (back), D Penisini (knee), T Morris (neck), P Matthews (ankle)
Previous meetings: In Welsh league matches Neath lead 9-7 on wins overall
and by 6-2 at home.Last season: Neath won 45-6 away and 50-8 home in league matches, but Ebbw Vale won 20-10 at home in the Principality Cup Round Seven.
Form guide: Ebbw Vale's only league wins at the Gnoll were by 16-15 in
1996/97 and 22-20 in 1998/99.
POOL A - EDINBURGH RUGBY v LLANELLI (at Meadowbank, 7.30pm).
Llanelli take their strongest available side to Scotland hoping to break their Meadowbank duck. The Scarlets have lost all three previous games Edinburgh's home stadium.
Scarlets coach Gareth Jenkins makes three changes from the side that beat Ebbw Vale 37-25 last weekend. Wales trio Stephen Jones, Iestyn Thomas and Robin McBryde come in for Gareth Bowen, Phil John and Marcus Thomas at fly-half, prop and hooker respectively.
Simon and Guy Easterby are unavailable for selection as they are included in Ireland's squad for the World Cup qualifier against Georgia in Dublin.
Jenkins says his Scarlets have to win all their remaining matches, and with Edinburgh pushing for top spot in Pool A, this will be no easy task.
Jenkins knows the Scarlets must raise their game in order to win.
"We are going up a class when we play these teams (Irish and Scottish) but that brings the best out of Llanelli."
Edinburgh: (not yet available)
Llanelli: G Evans; M Jones, M Watkins, L Davies, S Finau; S Jones, D Peel; I Thomas, M.Thomas, M Madden, V Cooper, L Gross, D Jones, D Hodges, I Boobyer. Replacements: J Davies, M Thomas, C Wyatt, L Cudmore, M Phillips, G Bowen, M Cardey.
Referee: S McDowell (Ireland).
Out - Edinburgh: M di Rollo (knee).
Llanelli: N Boobyer (foot fracture); S Easterby & G Easterby (on Ireland duty), S Quinnell (nose), D Williams (knee).
Welsh/Scottish League wins: Three each with neither side winning an away
Last season: Llanelli 42 Edinburgh 17; Edinburgh 40 Llanelli 8.
POOL B - BORDERS v LEINSTER LIONS (at Netherdale, 7.30pm).
Celtic League champions Leinster are desperate for a victory to turn their campaign around.
A defeat to Borders would surely end all hope of quarter-final qualification. The Lions beat the Scottish Borders in the 1996/97 Heineken Cup 34-25, and a repeat performance will take the pressure off coach Matt Williams, who has come under increasing criticism from a Leinster public used to success.
The Borders will be without wings Shaun Longstaff (groin) and Cammie Murray (shoulder), and are desperate for a change of luck.
They have lost three matches by a combined total of five points, including last weekend's heartbreaking one point loss to Pontypridd.
Borders: T Vili; N Walker, K Utterson, J Stuart, C Moir; G Townsend, G Armstrong (capt); P Thomson, S Scott, B Douglas, D Weir, R Metcalfe, C Feather, S Sititi, M Taylor. Replacements: S Paterson, C Laidlaw, I Fairley, A Rennick, C Stewart, C Dunlea, S Gunn.
Leinster: C Warner; J McWeeney, K Lewis, S Horgan, G D'Arcy; A Dunne, B O'Meara; E Byrne, P Smyth (capt), N Treston, B Gissing, B Kearney, D Dillon, V Costello, L Toland. Replacements: P Coyle, G Hickie, A McCullen, S Jennings, S Keogh, M Leek/G Browne, D Quinlan.
Referee: H Watkins (Wales).
Out - Borders: S Longstaff (Groin), C Murray (shoulder), G Morton (shoulder),
G Graham (calf), S Cranston (ankle).
Leinster: N Spooner, P McKenna, A Magno, E Miller, B Willis, B O'Riordan.
Previous meetings: In the 1996/97 European Cup, Leinster won away 34-25.
On the day the Wales U20 squad for the Six Nations is revealed, WRU Head of Rugby Performance Geraint John discusses the priorities of the Wales U20 programme, and moves being undertaken to make it easier for Welsh Exiles to be part of the WRU pathway - and to help keep Welsh qualified players in Wales
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Wales head coach Rob Howley explains his decision to change the captaincy of the national side with Ospreys second row Alun Wyn Jones taking over from Sam Warburton for the forthcoming RBS 6 Nations. Howley is hoping his decision will allow Warburton to rediscover his 'mojo'.
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Head coach Rowland Phillips and key front rower Carys Phillips look ahead to games against Spain and Ireland as Wales Women ramp up their preparations for the forthcoming Six Nations. The two warm-up games are a 'massive opportunity to refine the squad' according to the Welsh camp.
Martyn Phillips has discussed details of the newly published 'Strategy for Welsh Rugby' which puts in black and white terms the plans and direction of the governing body of the national sport in Wales for the next decade.
WRU chief executive Martyn Phillips has urged Welsh rugby fans to follow in the footsteps of their soccer counterparts at last summer's Euro Championship by backing their team to the hilt in the upcoming RBS 6 Nations campaign.
Chief executive Martyn Phillips has highlighted the plans for Wales to become a breeding ground for national and elite club rugby coaches, which are contained in the WRU's 10-year 'Strategy for Welsh Rugby'.
Andrew Coombs is enjoying his new role as Nelson forwards coach. The former Dragons and Wales lock has big ambitions to become a professional coach but feels it's important to learn the ropes in grassroots rugby and where better than his home club Nelson, with friends and family close to hand.
Students at Brynllywarch Hall School, near Newtown, have transformed their own lives, and are now having a positive impact on others through rugby. The sport has had a life-changing effect on the well-being of the students who are now delivering rugby sessions to local primary schools and playing for a new mixed ability side
Wales reached their first semi-final since 2013 in the opening round of this season's HSBC World Rugby Sevens Series in Dubai. WRU TV's Graeme Gillespie recaps on what proved to be an eventful tournament
Wales and Ospreys back row James King, who came through the North Wales age grade system, nominated North Wales Regional Community Rugby Manager Marc Roberts, in the WRU's 'Diolch' initiative where squad players thanked those who played a part in their rise to the top.
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.