Crunch time in Cork? What ever way you look at today's Munster-Ulster clash, it's certain to leave one in the top half and the other in the bottom, and ultimately it is hard not to think that it's a potential European Cup and/or British League qualifying play-off in the making. A big one then.

For Munster particularly, there wouldn't seem to be much room for turning back if they lose, as they then face a concluding trip to Donnybrook in three weeks' time whereas Ulster will have Connacht at home.

Indeed, were Leinster to win in Galway and Ulster to take five points from this afternoon's trip to Cork, then the cut-off would be complete and Ulster would be assured a top two place along with Leinster. Munster would be left with the left-overs, the European Shield and/or a British league second division next season. Disastrous really, and for them utterly unthinkable.

Munster might also have a whiff of vengeance in their nostrils after their distracted and self-destructive defeat in Belfast four weeks ago. Not that too many of them have survived, which is probably just as well.

All told there are eight changes in personnel from that nadir at Ravenhill, at full-back, centre, out-half, hooker, prop, lock and both wing-forwards. Declan Kidney has shuffled his deck more often than a card shark in one deal, but appears finally to have hit on a settled hand after using 33 players, this being Munster's first unchanged side since the interpro opener against Connacht.

Munster's graph also seems to be rising steadily upward, and today they seek a fourth successive home win and third on the spin in Musgrave Park. By contrast, Ulster have been through the treadmill a bit, and have failed to win any of their last three games.

By all accounts they capitulated a little in Toulouse, though they'll be grateful to have Andy Ward and Allen Clarke back in the pack. Harry Williams has also moved Dean Macartney across to number eight in a more dynamic-looking back row, though injury has sidelined Jan Cunningham (six tries in eight games), with Stanley McDowell returning on the wing.

Ward is their spiritual leader, all the more so in the absence of Mark McCall, and his presence will surely give Ulster a lift as well as a serious source of impact all along the gain line. Clarke's workrate, too, will add to the mobility of an unexceptional tight five.

Nevertheless, they seem to be resorting more and more to a kicking game from David Humphreys, and thus far the mercurial one has done it pretty well, producing neither a stinker nor a blinder. Very consistent. Very strange.

If anything Munster have become the more dynamic lately, and more worrying still for Ulster is that they've started to become a little porous, leaking 14 tries and 112 points in their last three outings.

Not only will Ulster be meeting largely different personnel, but a different team. The emergence of young Mick O'Driscoll against Neath a week ago gave Munster's tight five noticeably more mobility, with Mick Galwey and John Hayes having their best games of the season.

This gave the Munster back-row trio far more room to play, while the emergence of Barry Everitt as a true playmaker allowed them more attacking options, and the emergence of Cian Mahony gave the Shannon loosies a real midfield target to play off.

Presumably, Munster will have the courage of their convictions and the confidence to carry on from last week, thereby putting into practice what they've been preaching. Both sides have good, varied line-outs to attack off. Munster might have an edge here too, their clever, well-honed moves yielding four tries in their last three outings. Therefore, it could and should be the best game of the season in Munster so far, provided Gordon Black lets it flow. And Munster look better primed to win it.

Munster: B Roche; J Kelly, M Lynch, Cian Mahony, A Horgan; B Everitt, B O'Meara; P Clohessy, M McDermott, J Hayes, M Galwey (capt), M O'Driscoll, A Quinlan, A Foley, E Halvey.

Ulster: S Mason; S McDowell, J Bell, C van Rensburg, S Coulter; D Humphreys, A Matchett; J Fitzpatrick, A Clarke, G Leslie, M Rea, G Longwell, S McKinty, D Macartney, A Ward.

Referee: G Black (Leinster). LEADING POINTS SCORERS: Munster - Killian Keane 44; Ulster - Simon Mason 47.

London Irish, jubilant following their shock win at English Premiership champions Newcastle last Sunday, give a full League debut to 20-year-old former Millfield School pupil James Brown, who replaces Matt Jones, for this afternoon's match at home to Richmond. The side is otherwise unchanged.

London Irish coach Dick Best admits that his team have made themselves a target after inflicting Newcastle's first-ever Premiership One home defeat. "That high-profile win will put people on our case," he said.

Richmond could field captain Ben Clarke for the first time since September 12th, when he suffered a shoulder injury against Gloucester.