Sideline Cut:No matter how passionately the air of Flower of Scotland is delivered around Edinburgh this weekend, it will hardly be enough to prevent Ireland claiming another Triple Crown.

After all the mysticism and emotion attached to the last two internationals in Croke Park, Irish fans will fill the taverns of Princes Street this weekend on the assumption that the latest meeting with the Scots will be a merry coronation. Unless Ireland suffer from the kind of slump associated with the Asian stock market, the public will not be disappointed.

And afterwards, Eddie O'Sullivan will appear on television to the nation, tie neatly knotted and blazer closed, and squinting into his mental portfolio of the game, he will declare himself reasonably happy with the "Test" victory, adding a cautionary note about the dangers and difficulties of finishing the season out on a high in Rome.

There is no question this has been the season of absolute content for lovers of Irish rugby and that much of the success has been built around O'Sullivan's fussy and careful architecture. Yet the more we see the Irish coach talking, the more inscrutable he becomes. He took the heartbreakingly late loss to France in Dublin with barely a wince, and his expression had hardly changed a fortnight later, when Ireland produced their beautiful game against a hapless England to thrill a rapturous crowd in Croke Park.

In his early days as Irish coach, the Youghal man acquired the sobriquet Steady Eddie. The nickname reflected his caution, his compulsive attention to detail and his mistrust of the radical. But it was not the most flattering or affectionate of sporting names.

O'Sullivan never set out to gain the affection of the media, and over the past four years he has had his critics in print and on television. It is less than two seasons since one national newspaper led with the back-page headline "Steady, Eddie, Go".

In 2005, Ireland were flat in the Six Nations and uninspiring in the autumn series, notably crucified by New Zealand and providing a blunted Wallaby outfit with their first victory in nine games. O'Sullivan stood accused of fitting a bunch of expressive and creative rugby players into a straitjacket, of quelling inspiration with a barrage of statistics and percentages and a robotic game plan.

In 2004, Gordon D'Arcy's unexpected maturation from schoolboy prodigy to the Six Nations "player of the tournament" was regarded as emblematic of the revolutionary talent in Irish rugby. Fleet Street raved about the dancing feet of the Irishman and purred at the prospect of the Celtic magic he would work with Brian O'Driscoll. When that did not materialise the following season, the fast assumption at home was that O'Sullivan had smothered the new boy's flair to make it fit with the system.

O'Sullivan rode the storm. He went on the attack to defend his team, castigating the description of David Humphreys as a coward and questioning the dismissal as "crap" of the Irish frontrow.

There was always a contradiction in the notion of O'Sullivan as a dictator in that he clearly regarded himself as an outsider when it came to the Irish rugby establishment. He came to the Irish position from the most oblique angles, learning his trade on the sweltering, inconsequential fields of American rugby before finally attracting some home attention. When he succeeded Warren Gatland, there may have been substance behind the grievance at how the New Zealander was treated by the IRFU. And one could not but be struck by the difference between Gatland, who could be blokeish and charming, and the more pinched and serious and distant figure of O'Sullivan.

Early in 2005, I met O'Sullivan in a cafe in Tuam, not far from his home in Galway, for the purpose of an interview. He spoke engagingly for 90 minutes, but the phrase that stuck with me was, "I had no pedigree."

He was talking about his playing days with Garryowen and Munster and the subtle significance of not having schooled or socialised in the distinct stratosphere of Irish rugby tradition.

From the beginning, O'Sullivan's was the classic sports story of having to prove himself twice over at everything. And so he pumped weights with ferocity long before that was in vogue, and as a coach he collected a library of innovative sports theory and psychology. And as the IRFU made the move from joke-professionalism to actual-professionalism, he fitted the bill: a CEO with studs and shorts who could prepare for and analyse the game as though it were a business proposition as much as a team pumping with real people and emotions and doubts.

From a distance, O'Sullivan's ways may seem cold. And he certainly has the ruthlessness necessary to steer the Irish team as he wants to, gently but firmly closing the door on the international career of Anthony Foley, a gargantuan folk hero, and giving fans of Geordan Murphy a miserable season with his selection policy.

O'Sullivan makes the calls as he sees them, and if he worries about the consequences he keeps that private.

The impression I formed of O'Sullivan that day two years ago was not of a cold man but rather of a sportsman absolutely determined not to slip up. He probably knows he is fortunate to have assumed the Irish post in an era containing Brian O'Driscoll, Ronan O'Gara and Paul O'Connell in their prime. He will probably acknowledge too Ireland have benefited from England's cataclysmic fall from grace in the past four years. The ex-ball-player in O'Sullivan is probably seriously in awe of talents like Denis Leamy and Denis Hickie and, indeed, the unfortunate Murphy. But as coach, he believes in thinking out every move, predicting every pitfall.

Emotionally draining as the last two minutes of the French game were for Irish fans, they corresponded perfectly with Eddie O'Sullivan's philosophy of sport. For the briefest moment, Ireland lost concentration and they were punished. That is what happens. Nine times out of 10, they might have got away with it.

Those chinks, those weaknesses, are what O'Sullivan obsesses about. He does not go in for blustery swagger about pride or patriotism. Nor does he make grandiose claims about rugby being the national game (the man lives in Galway; he knows better). That stuff he leaves to George Hook and the champagne set-up in studio.

Instead, Eddie burns the midnight oil planning and strategising and works his team on the training field. He probably knows this cannot last. Triple Crowns may not matter as much to Ireland as they did back in the days of the garrulous, charismatic Mick Doyle. But they do not come around too often and are not to be scoffed at.

Today should represent another feather in Eddie O'Sullivan's cap. But the quiet man, the man with no pedigree, must surely have next September and the World Cup on his mind. The world stage of rugby beckons and Ireland may never have a greater chance to shine. Only then - and only if Irish rugby becomes the toast of the tournament - will the steady operator permit himself the impresario's bow.