It is not quite as difficult as splitting the atom; almost, but not quite. On the pitch Ronan O'Gara and his partner at halfback, Peter Stringer, are the nucleus of much of Ireland's stratagem and they are as close to inseparable as makes no odds.
They are an item, in the purest of senses, and have been since they first played alongside each other as schoolboys at under-eight level. It is, therefore, perhaps a little bizarre to prise them apart, singling out one to deal with in his own right and leave the other in shadow, as it were.
Even when the split has been achieved it is not a clean break; the one is never far from the rugby thoughts of the other. So it was with O'Gara, the fly-half of the partnership. He is slightly ill at ease; uncomfortable when talking about himself, too ready to change the subject to scrum-half Stringer. He needs coaxing before a clearly independent streak is revealed.
"When I go on a pitch, I trust my instincts," he declares. "It means I don't feel as if I am playing the coach's game, I feel like I am playing my own game. Although obviously paying heed to the overall game plan.
"But, the thing is, when you are out there in a match you have to read what is in front of you at any given instant. And that is not something that can be coached."
O'Gara was 23 three weeks ago and has just three caps. But already, in that short space of time, he has learned that caps are not simply lifted off a peg. They are hard won. His debut was a perfect lesson. It was against Scotland and, although Ireland triumphed, it did not go quite as O'Gara had planned.
"I thought that things would happen for me without me having to do my homework," O'Gara confesses, "without me having to think a phase or two ahead in the game, without me having to work out what I needed to do as an out-half."
He was replaced midway through the second half and a delighted David Humphreys showed him how to do the job. O'Gara was disappointed and even began to think the doubters were right and that he had blown his chance, that Humphreys would win back his place.
There were certainly knots of dissatisfied and disappointed punters, who had been swept along in the boy-wonder hype that swirled around the man. O'Gara says: "I took a lot of criticism for my performance against Scotland, but I feel that there were positive elements to my game that day. I had to learn on the hoof against the Scots."
He had no idea how the selectors had viewed his performance. "I just had to hope that I would have a run-out against the Italians so that I could show I could take the sort of game I have been playing for Munster up to international level," he explains.
Fortunately, the Ireland coach, Warren Gatland, agreed with him. On the same Lansdowne Road stage two weeks later he trotted out with Stringer at his side to take on the Italians. "I concentrated an awful lot harder against Italy," he says, "and that is the way I have played since, the way I will continue to play."
He was still replaced by Humphreys in Paris a fortnight ago and is honest enough to admit: "I can't say that I enjoy coming off and giving way to David Humphreys."
However, the professional, the realist, the wiser young player in him allows: "But these days rugby is a game for 22 players, not 15. There is no point being annoyed or feeling bitter at being taken off, because to have been part of it all is just great anyway.
"And I suppose whether I start a game or he does is immaterial, it all comes down to wanting to be a part of the action, getting as much of it as you can."
The words begin to flow as he deftly steers the burden of attention on to Humphreys and away from himself. "I think he and I have brought out the best in each other anyway. He has risen to the challenge now with me coming in and taking his place." And he has the humility to say: "I think he is probably more astute at the minute in his kicking game. I have struggled a little bit with that aspect of my game."
He is happy with some of what he does, though; O'Gara has good hands and creates openings for others. But, of course, he can only play as he wants if his partner provides quality service. Fortunately Stringer does. He is magnificent. Together they form a double-headed beast capable of monster performances.
O'Gara acknowledges that the scrum-half's stunningly flat and fast pass gives him an edge. "I stand up flatter to Peter and I still have plenty of time on his pass," he says, a lot more at ease now, as the focus of attention widens to take in his partner. "When we first stepped up to international level where the pace was probably beyond both of us at the start we realised we had to introduce a call to differentiate between kicking and running ball, something we had never had to do for Munster, or any other level. It has worked out well."
Because of Stringer, oddly, O'Gara can be his own man on the pitch. "My role is as a disputer," he says, "eyeing up what is on, so I stand flat. It is the way I have always played. I am not afraid of the back rows. There is nothing more annoying that sitting deep in the pocket, there is not as much of a challenge anymore playing that type of game. A flat game is the only way I know, really. It's an in-their-faces approach."
His fourth cap is going to be as hard won as any. Tomorrow in Dublin Wales will most certainly have O'Gara in their faces - unless or until he is replaced - and when he is not there the chances are it will be too late to worry, the mighty atoms at half-back for Ireland will, as like as not, have inflicted serious damage to the Red Dragon cause.Reuse content