Six Nations 2016: From Lawes to Roberts, meet the biggest hitters
They are the men who think defence is about attack, the big-hitting bruisers who relish lining up the opposition runners and smashing them back where they've just come from.
Powerful, ferocious and never happier than when levelling someone from the other side, these are Six Nations Demolition Men - the half-dozen most destructive tacklers in the tournament.
We've ranked them in order from first to sixth. Do you agree? Or have we missed out the most damaging demolition man of them all? Have your say below.
When World Cup-winning England captain Martin Johnson talks admiringly about your tackling - "when he hits players there's a distinctive noise" - you know you've made an impact, and making an impact is what England lock Lawes does best.
Outstandingly quick and athletic for his 6ft 7in frame, Lawes demonstrated his appetite for destruction with a memorable tackle on France fly-half Jules Plisson last season.
Shoulder injuries have hampered him and he was quiet as England limped out of their own World Cup last year, but there have been signs he is returning to his destructive best and, with Eddie Jones calling for more aggression from the England pack, the new coach will be hoping Lawes wreaks havoc over the next six weeks.
Back rowers are supposed to make the most tackles, but nobody seems to have told Scotland second row Jonny Gray.
The baby brother of fellow Scotland lock Richie - he doesn't turn 22 until the final week of the Championship - Jonny was the leading tackler in the 2015 Six Nations with 84, and had just a solitary missed tackle.
It is not just Gray's industry that gets him on this list, because others have a high work-rate too, but also the destructive nature of his tackling - and at nigh-on 19 stone and with his power increasing by the year, the youthful Glasgow Warriors second row looks likely to be smashing people for many years to come.
He's been at the heart of the Welsh pack for a decade and has won a century of Test caps, but there's little sign of the second row's ferocity waning.
It's an age-old adage that the scariest hard men are the ones who are also intelligent, and law graduate Jones twins a high IQ with an unmatched relish for the physical side of the game.
Once described as rugby's angriest person - he prefers to think of himself as a "happy angry" person - even his own team-mates can find him intimidating, and the opposition know that from the first minute to the 80th Alun Wyn will be lying in wait to hammer them backwards every time.
He's as happy with ball in hand as he is tackling people, but England number eight Vunipola is just as dangerous in defence as he is in attack.
One half of England's Righteous Brothers with prop Mako - he is heavy, he's my brother - Billy manages to weigh in a few pounds shy of 20 stone despite 'only' standing 6ft 2in.
Amazingly mobile for someone apparently built out of a slab of granite, the younger Vunipola leaves opposition players scattered across the field in both attack and defence and hits as hard as just about anyone on show in the Six Nations.
Another renowned as much for his carrying as his tackling, there is no doubt that flanker O'Brien is one of the biggest hitters in the Championship.
The Tullow Tank attributes his power to "farmer strength" earned over the years wrangling cows on the family farm, and when you've manhandled recalcitrant bulls since childhood, taking down a rampaging opposition number eight must look like an easy afternoon's work.
As happy hitting rucks - watch the bodies fly when O'Brien arrives at the breakdown - as he is tackling one on one, O'Brien's brand of bullocking rugby makes him one of the finest Demolition Men on show.
The only back to make it into the 2016 top six, when the doctor is in residence opposition players know they are in for a world of pain.
Dr Jamie Roberts - he is currently studying for an MPhil in medical science at Queens' College, Cambridge - is the second of the intelligent Welsh hard men in this list, and while Alun Wyn Jones prefers to take care of business in the tight and around the fringes, centre Roberts operates further out.
As a blockbusting inside centre, the Welshman is faced by opposition players coming at pace and from depth, and when they arrive the good doctor is likely to dish out treatment with results more akin to a sledgehammer than a scalpel.