When Louis van Gaal was Ajax coach in the mid-1990s, taking an astonishingly young and talented side to a memorable European Cup triumph, he didn't view his players as people.
Instead, they were merely numbers.
That was something of an Ajax tradition -- there were particular roles for the players who wore the No. 6 shirt, the No. 8 shirt, the No. 10 shirt. With a similar system being deployed throughout the club -- either 3-4-3 or 4-3-3 -- it meant Ajax's youth players could step up into the first team seamlessly.
The responsibilities of the No. 6, for example, a battling but efficient deep-lying midfielder, were always consistent. It remains true to this day, and at the World Cup, Van Gaal's first Netherlands XI wore 1-11 for their 5-1 thrashing of Spain - the No. 6 was Nigel de Jong.
It was Rinus Michels, the legendary inventor of Total Football, who started using numbers in this fashion at Ajax. It emphasised a clear philosophy, that the players were simply part of a wider structure, rather than given individual freedom to make their own positional decisions.
His protégée, Johan Cruyff, was very different. He looked more at the personalities of players, having expressed his individuality as a player.
Van Gaal reverted to the rather po-faced, distant approach of Michels, who later declared himself a huge admirer of Van Gaal.
"[Van Gaal] works even more structurally than Cryuff did," he wrote in his seminal book, Teambuilding.
"Van Gaal gives much attention to the team building process using a perfectly structured youth football education system as the foundation. Compared with 'Total football', there is less room in his approach for opportunism and changes in position. On the other hand, the build-up [play] is perfected to the smallest detail."
Michels and Van Gaal, incidentally, both started their professional life outside football, in the same.
"Michels was a PE teacher first as well," Van Gaal once said. "Players are just like big children. So there really is a resemblance between being a teacher and being a coach."
Big children? Already, you can tell the Red Devils manager isn't looking for any dissent from his pupils.
Such a systemised approach to football is particularly interesting given Van Gaal has already completely changed Manchester United's formation. He's already introduced the 3-4-1-2 system he used so successfully with the Netherlands at the World Cup, although he is more flexible in his approach than some have suggested. Indeed, while 3-4-1-2 was his default approach in Brazil, he also used 3-4-3, 4-3-3, 4-2-1-3 and 4-3-1-2.
The switch to 3-4-1-2 at Manchester United is fascinating, however. While Sir Alex Ferguson's approach changed over the course of his reign, he almost always played with a four-man defence. There were emergencies when he switched to a back three, but that was due to a lack of defensive personnel, rather than a cunning tactical move.
Van Gaal's approach is something entirely new to Manchester United. The biggest change will come at the back, but the major beneficiaries will be the attackers.
Switching to a three-man defence isn't simple for players unaccustomed to that shape. Van Gaal's use of that system with the Netherlands was largely dependent upon the fact four of his first-choice back five played together in that system for Feyenoord towards the end of 2013-14. There, they had been taught in that system by Ronald Koeman, who had worked as his assistant at Barcelona between 1998 and 2000 -- it couldn't have worked out better for the national team manager.
The trio of Chris Smalling, Phil Jones and Jonny Evans will play much higher up the pitch, remaining relatively close together and sticking tightly to opposition centre-forwards.
The pursuit of Arsenal's Thomas Vermaelen makes sense -- schooled in the Ajax system Van Gaal helped to create, he got himself into difficulties at Arsenal because he exhibits that approach too much.
He was always coming out from his centre-back position and sticking tight, leaving space at the heart of the defence. Arsenal simply don't play that way, but Van Gaal's system will ensure there's always a spare defender to sweep up, and the Belgian could rejuvenate his career at Old Trafford.
The midfield will be primarily about two concepts. Without the ball, Manchester United will press. This explains the addition of Ander Herrera, the feisty, energetic all-round midfielder from Athletic Bilbao -- he's not a holding midfielder, but his tackling statistics are always extremely high. He pushes up the pitch and goes looking for challenges.
In possession, the key is switching play. Herrera and Michael Carrick -- once he returns from injury -- will play simple but very deliberate, methodical passes into wide positions. As Michels says, the buildup play in Van Gaal's sides is always very intelligent.
However, the really exciting zone is upfront. The 3-4-1-2 system, along with a similar alternative, 4-3-1-2, are the only shapes that allows Juan Mata, Robin van Persie and Wayne Rooney to play in their best positions. Three of the Premier League's best attacking players, they're both highly efficient and very selfless -- expect some staggeringly quick attacking exchanges between them.
Mata as a No. 10 is most exciting. He thrived in that position under Rafael Benitez at Chelsea, but this is even more of a classic version of that role.
At Chelsea it was in a 4-2-3-1, but this 3-4-1-2 shape means both opposition centre-backs will be occupied, and Mata should find space between the lines to work his magic. Rooney and Van Persie, meanwhile, need no introduction - the title-winning strike partnership from 2012-13 remains devastating when motivated, and provided with good service.
Interestingly, with a week until the start of the Premier League campaign, Manchester United's squad numbers are yet to be unveiled. New signings Luke Shaw and Herrera haven't been allocated numbers, with the 3, 5, 7, 9 and 11 shirts all up for grabs. They might be advised to choose carefully -- for Van Gaal's Manchester United, they will be numbers, not people.