LONDON - It's a feat that has been beyond some of rugby's greatest teams.
The exhilarating Welsh side of the 1970s couldn't do it. Neither could the Philippe Sella-inspired French in their golden age of the mid-to-late 1980s. Clive Woodward's England came close at the start of the 21st century but again fell short.
On 20 occasions, a country has won back-to-back titles in the northern hemisphere's top international championship — its name has ranged from the Home Nations, the Five Nations and, currently, the Six Nations — but none have managed three in a row outright.
Heading into the 120th edition, England's class of 2018 is the latest team aiming to reach that elusive milestone.
"We want a 'three-peat,'" England coach Eddie Jones says.
The English have already made history in Jones' two years in charge, winning 18 straight tests to break the national record and match a world-record streak set by New Zealand.
Throw in two straight Six Nations titles and a rise to No. 2 in the world ranking, no wonder the Rugby Football Union recently tied Jones down to an extra two years, keeping the Australian at the helm until 2021.
The hard work might just be starting for Jones, though.
After the honeymoon period, he says England has entered Phase 2 of his tenure. All roads point to Japan for the 2019 Rugby World Cup and Jones wants to be sure England has the necessary strength in depth to sustain a genuine challenge for the trophy.
The next seven weeks might answer that.
This edition of the Six Nations could just as well be dubbed "Survival of the Fittest," given the injury problems that are wreaking havoc across European rugby.
England says it has 18 players out of contention for various injuries. Wales has fewer players sidelined but they'll arguably have bigger names missing, including Liam Williams, Sam Warburton, Dan Biggar, Rhys Webb, and Taulupe Faletau.
Morgan Parra and Brice Dulin have just joined France's lengthy injury list.
Ireland coach Joe Schmidt has said he has "13 guys that were selectable who may or may not get back during the championship."
Putting aside the longer-term questions about player welfare in this brutal age of rugby, the short-term effect is potentially a more competitive Six Nations.
Ireland won consecutive titles before Jones arrived on the scene, and looks to be the biggest danger to England, on the back of a November series in which Schmidt's side beat South Africa — by a record 38-3 — and Argentina in a clean sweep. It was the Irish who ended England's hopes of consecutive Grand Slams with a 13-9 win in Dublin in March.
Scotland's 53-24 win over Australia in November, dovetailed with a narrow loss to New Zealand a week earlier, suggested a team that has developed its attack in recent years could be even more of a threat under new coach Gregor Townsend.
France is also under a recent hire in Jacques Brunel, and has 10 players in its squad under the age of 23, making Les Tricolores as hard to predict as ever.
Its injury crisis, as well as away matches against England and Ireland in the first three rounds, will likely see Wales fall short.
Italy, in its second season under Conor O'Shea, is once again the wooden-spoon favorite.
So don't discount England's chance of making more history under Jones.
Such is his diligence that England's coaching team said last week that it is using a tactic utilized by the U.S. military in the Cold War to help prepare the side for unlikely eventualities in the Six Nations.
"We're militarily red-teaming our own side to see what weaknesses we have shown and where we think we can improve," defense coach Paul Gustard said about the twice-a-week meetings on 'what if' scenarios.
The spark for this was Italy's no-ruck tactic that bamboozled England in a match at Twickenham last year. The English came through that difficulty and won — as has often been the case under Jones.
Expect, like last year, England vs. Ireland to be the title decider in the final weekend.