On Syokaun-Dori Avenue, about a half-hour train ride away from Tokyo Stadium where Johnny Sexton, on Friday, went through the captains run under heavy cloud cover, hard-charging city bikers like to wait until the lights turn green so they can then wheelie through the hundred odd-metres of open road in front of them, their machines screaming through a patch of the city where the bars stay open from early until early and the street soundtrack seems permanently set to Heartbeat City by The Cars.

And its just there, if you walk down the narrow alley between Sushi Zanmai restaurant and the Family Mart convenience store and keep going past the dentists and the small family homes, that you will come to the modest plaque at the elementary school marking the former home where Patrick Lafcadio Hearn died.

He remains Japans most famous Irishman and was gone in 1904, a year before Dave Gallaher took his New Zealand team on the tour of the old countries which started the All Blacks rugby furnace.

The only connection between the two men is a kind of restlessness and the creation of a new identity common to so many epic Irish stories. Hearns story has been well documented over this World Cup: his personality shaped by the horrific fact of his abandonment, in Dublin, by his Irish father and Greek mother before he was moved like an unwanted parcel by relatives from London to America, where he became famous as a journalist and writer, before discovering Japan at the age of 39 and never leaving.

By the time of his death 15 years later, he had achieved a kind of sacred status as a tireless collector of Japanese ghost stories and myths, had changed his name to Koizumi Yakumo, and had at last both psychically and geographically placed an enormous distance between himself and his grim early years in Victorian Dublin.

He was into trippy imagery, but its hard to know what Hearn would have made of Tokyo this weekend, with many thousands of Irish faces and accents drifting through the metropolis on their way down to the game.

The build-up to this quarter-final has been neutral on the surface, but its not hard to detect a slightly tetchy edge about New Zealands attitude to Ireland right now: that the feisty if once-reliably beatable party animals from the land that gave them Gallaher has become an itch they just cant wait to scratch preferably through a scatter of breathtaking tries.

Not for the first time, the issue of the Haka has been brought up at both media briefings and the responses from both squads predictably measured. The Haka is a ritual that will always divide opinion but, whatever advantage it does or does not give the New Zealand team, it is regarded as a jewel in the crown by World Rugby because the spectators love it. At all New Zealand games, the Japanese fans have been thrilled by the spectacle. And the Haka is a part of New Zealand culture: their national rugby team is entitled to interpret it as they see fit.

But what is interesting about the pre-match rituals in Saturdays game is that the symbolism and meaning behind Irelands chosen anthem is so often and so easily overlooked on these days.

Its probably to their credit that Ireland rugby as an entity have never made that much of a deal of the fact that even through the most poisonous and strained of times on the island of Ireland; even when the deaths were everyday occurrences and, in act and deed, beyond the darkest imaginings of anything Lafcadio Hearn might have dreamt, that the rugby fraternity managed to scrabble together southern Catholics and Ulster unionists with no common ground except for their love of the game. That they played together was, in the bleakest years, a tiny but vital reason for optimism. It was a small miracle that at least that much held.

Donal Lenihan, the former Ireland great and RT analyst, has spoken and written entertainingly about the shambolic prelude to Irelands inaugural World Cup participation in 1987 when, days before the game against Wales, the squad held urgent debates as to what song they should sing if any at all.

Wales would lift Eden Park with their rendition of Land of Our Fathers. Three of Irelands rugby international stars Nigel Carr, Philip Rainey and Davy Irwin had, that April, been incidental casualties in the massive republican car bomb which killed Lord Justice Maurice Gibson and his wife. The trio had been travelling to Dublin for international training. It was a startling illustration to all living in the South of what happened if you happened to be in the wrong place at the wrong time.

Carr never played rugby again. Trevor Ringland, travelling separately, was just five minutes up the road. Jimmy McCoy, an RUC man, was heading to training on a train. He told Tom English in his acclaimed book No Borders that he immediately wondered if theyd been trying to get him. I always thought if they wanted to get me, they could get me. Representing Ireland, standing in Lansdowne, listening to Amhrn na bhFiann was hotly contentious and even a dangerous business for the players involved. It was a fraught time.

In 1987, the Irish teams chose James Lasts The Rose of Tralee as a last-ditch compromise. It went disastrously. By 1995, Phil Coulters Irelands Call was unveiled and was simultaneously acknowledged as appropriately safe and derided as an assault on music. The Derry man didnt care. It was there as a compromise, he told the Guardian just this year. And it has proven stubbornly resilient and serviceable. It has earned a kind of begrudging acceptance over the years through the absence of an alternative.

Over the past three years, as Brexit has forced a hardening of positions and attitudes in the North, memories of the pure horror and mental torture of daily life across Ulster have become sharp and refreshed. And, as the clock ticked and Westminster descended into chaos, tens of thousands of people across Northern Ireland must have shuddered at the thought that two decades of relative serenity and normality might again be threatened.

It was probably coincidental that Ireland enjoyed a golden era of rugby success in that period. But the rugby traffic across the border improved dramatically as supporters from the south made journeys for games in Dublin and Belfast that they simply wouldnt have dreamt of making during the worst of it. Ravenhill and Belfast afterwards became a good night out.

Its a good bet that people from all backgrounds and persuasions will sit down in front of the television on Saturday morning to see how the one strand in Irish life that remained united through the violence will get on in the big match.

And in the minutes beforehand, the world will pay attention to the Haka: the menacing Maori dance will steal the show. And that is fine.

But its worth remembering that when Rory Best leads off Irelands Call for what might well be the last time in his career, the vanilla words and wilfully safe music will run deeper than mere symbolism and hold the spark of what might be the most meaningful achievement in Irish rugby that its national team, its players from all corners, stayed soldiering through the worst of it so subsequent Ireland teams like this one might enjoy the best of it.

Read more:
Vanilla words of Irelands Call an unlikely antidote to bitter divide - The Irish Times