ONLY four nations have ever won the Rugby World Cup. Just one other has been a finalist, and merely three more have made it to the last four.

Since its inception in 1987, the tournament has been a showcase for concentrated excellence in the sport. There have been few real upsets, partly because of the nature of rugby itself, but largely because the leading countries have always been able to marshal their considerable resources into ensuring they are at their peak when the four-yearly event comes around. Club and provincial rugby has grown immensely since the Webb Ellis Cup was first won, but the international game still holds sway in a way it has no chance of in the far richer sport of football.

Although a relatively recent addition to the rugby calendar, the tournament has played an influential role in the history of the sport as a whole. Initially a response to the drive for greater competition from those countries – above all Australia, New Zealand and France – who were in favour of a move to professionalism, it soon became the catalyst for giving that move unstoppable momentum.

The first event took place in 1987 after years of opposition from the home unions, who remained in favour of a strictly amateur game. Even then they were swimming against the tide, something the Scottish Rugby Union would continue to do until months before the sport finally reached a global agreement that it should allow professionalism.

That agreement was struck in 1995 at the third World Cup, which saw Jonah Lomu become one of the best-known sportsmen on the planet. Having witnessed Lomu’s ability to appeal well beyond the traditional boundaries of his sport, Rupert Murdoch made a deal with Australia, New Zealand and South Africa to fund the Sanzar Cup, an annual tournament between them.

The All Blacks of that year were the most exciting and audacious team ever seen on the rugby field, and yet they lost the final to their South African hosts. As the nation to whom rugby matters most, New Zealand has always seen winning the trophy as a vital way of proving its status to the rest of the world. After becoming the first winners, the All Blacks could do no better in 1991 than defeat Scotland in the third-place play-off, but it was that failure in 1995 that turned an eagerness to win into an obsession that has at times been self-defeating.

In the best match of the 1999 event, the French stunned New Zealand with a magnificent display in the semi-final at Twickenham. In 2007 they did so again in the quarter-final in Cardiff. The All Blacks should stroll safely through Pool C this time round, but they will be keeping an anxious eye on Pool D, from which France could emerge as their last-eight opponents.

Of course, results between those two countries are by no means one-sided. Having gone no further in 2003 than a third-place play-off in which they overwhelmed the French, New Zealand at last justified their status as perennial favourites in 2011, beating the same opponents 8-7 in the final. It remains to be seen if that victory has made them any more able to deal with the pressure of the quest for the trophy.

Argentina, buoyed by their performances in the Rugby Championship, should go through as runners-up to New Zealand in Pool C, which would give them a quarter-final against the winners of Pool D, in which Italy will hope to upset the odds and qualify at the expense of Ireland or France. The last match in that pool is between the latter two countries, and could become the outstanding game of the group phase.

While those two pools should go with the seeding, there is no such certainty over the other two. In Pool A, England, the tournament hosts, come up against Australia and Wales – who play their games against Uruguay and Fiji at their own Millennium Stadium, the only venue outwith England. The outcome could be decided by the meeting of the Welsh and the Wallabies at Twickenham, although Wales’s recent loss to injury of Leigh Halfpenny and Rhys Webb might just have tipped the balance of probabilities against them.

Pool B is fought out over the entire length of England, from the north-east to the south coast. Scotland sit out the opening weekend, in which South Africa and Japan then Samoa and the United States go head to head in Brighton. The Japanese only have four days to recover before going on to Gloucester to play Scotland, who then move north to Leeds to face the USA before concluding with two matches in Newcastle.

On the map, Scotland’s schedule looks like a gradual retreat northwards, and it is easy to imagine some wag, when the pool fixtures were agreed, suggesting that a loss to Samoa in their last game at St James’ Park would at least mean the Scots had a short trip home. But the World Cup warm-up matches, in which they beat Italy twice and lost narrowly to both Ireland and France, have put Scotland in a far better frame of mind than they were at the end of a Six Nations Championship in which they finished bottom of the table without a win to their name.

Samoa are second seeds behind the South Africans, having been in the top eight of the world rankings when the draw was made. As ever, they will present a fearsome physical challenge, not only to Scotland but also to a Springboks side whose morale has been shaken by their loss to Argentina in the Rugby Championship.It is no coincidence, however, that the current Scotland squad is one of the heaviest and most powerful ever assembled.

You would still expect the Springboks to go through as group winners, and Scotland to shade it against the Samoans. That would generate quarter-finals between South Africa and the runners-up from Pool A, and Scotland and the winners. Both quarter-finals will be held at Twickenham. If Vern Cotter’s team come up against England, there would be no better time for them to record a first victory at the west London venue since 1983.

A prediction made with the heart rather than the head suggests that Australia will make it into the last four, where they will lose to their old foes New Zealand, and that Ireland – the only one of the home nations yet to reach the last four – will confront England in the other semi-final. Whoever wins that one will be favourite to come off second best in the final to the All Blacks, who would then become the first country to win the competition three times.