Rugby is layers of expression with victory orchestrated by those whose top two inches is in the best working order.
Scrum leaders work on similar measurements as they integrate their eight men for the contest with the opposing octet. For some spectators that is a starter move which gets in the way of the game, for others like Crusaders' scrum coach and former All Black prop Dave Hewett, it is a fascinating segment of the match.
"It is physical, it is mental, it is the coalface and you can't get closer to a fight or combat without guns, than at scrum time," he said.
If lineouts are aerial scrabble, then scrums are terra firma chess.
While backlines try to manipulate defenders so they can create chances, it is no different in scrums.
"Rather than doing it over metres you are doing it over centimetres," said Hewett.
"It still has the same impact on the game, there are still the same requirements about doing your job, you are just not doing it out in the wide open spaces."
Hewett played 22 tests then worked his way through professional and technical development at the Crusaders academy, as manager of the ITM Cup squad and now scrum and technical coach with the Crusaders.
He was a disciple of Mike Cron and has put his flavour to the broad outlines he learned from the scrum guru.
He does not study much archival footage because the game and its rules have changed so markedly. Instead he looks at a range of sports like wrestling, judo, plyometrics and gymnastics and applies those learnings to gym sessions, weight training, core and technical work for his squad.
Hewett is always reviewing the Crusaders' scrum details but concentrates on studying the opposition like the Chiefs.
"It is no different from backs looking at what their opponents' plays might be. You want to exploit rivals or deal with areas of the game," said Hewett.
Eyebrows were raised when Ben Franks replaced his younger brother Owen at tighthead for tonight's semifinal in Hamilton but Hewett explained they had to manage their test players.
"We can't have guys of the pedigree we have, sitting on bench for a time because they will get a bit rusty. They need to be working and engaged and we have confidence in all three."
Hewett defines a good Crusaders scrum as smooth, accurate, crisp delivery of possession to the No 8 or halfback.
"On the opposition ball, it is applying as much pressure as you can, from a legal point of view. I don't like walking around, it is a tactic which should be discouraged even though the rules seem to permit it. I think it is a negative tactic," Hewett said.
The four stage crouch, touch, pause, engagement might finish later this year although Hewett was not too sure about the wisdom of that move.
"We are just getting comfortable about the current ideas and officials are, too. I understand the idea of eliminating a verbal pause but if the rules are policed correctly then nine times out of 10 you get a good scrum. When referees rush calls or one team jumps a shade then you get a mess. If we keep tweaking it we will never get it right."
The Crusaders seem to do just fine though. They are lighter than many rivals but always seem to get parity or dominance.
"It is just technique and each player making sure they have their area of the scrum right. If they all do that then we are away.
"It does not matter how strong you are, technique will always win out. If you put the two together then you can be even more dominant."
Was there much more to go in the evolution of the scrum? That, said Hewett, would depend on the lawmakers. There would always be small improvements.
"It is like the 100m at the Olympics, "Hewett explained. "Whoever gets from one end to the other in the fastest time wins, providing you are not breaking any rules. You make small improvements each time but they get smaller each time. It is the small detail which is key."