At some point in the 1930s football, or at least British football changed or at least began definitely to do so. By the 1950s that change was in large measure complete but it had begun twenty years earlier before the War and with Herbert Chapman and Arsenal F.C. as it in England became and remained the most successful club of the decade. 

Herbert Chapman himself would die in early 1934 so he was responsible for the initiation of the change but not its completion. That lay in others hands and there can be arguments elsewhere about whose, but they were not George Allison's. He was not a football man in the way Chapman had most certainly been. In fact Herbert Chapman, despite being English to the core, had been a disciple of the Scottish game. His greatest on-field success had been gained under the guidance of  John Cameron at Spurs, where he had been groomed as one of the replacement of Cameron himself as the Ayr man's legs had started to go.

John Cameron's team set up, the one he had in 1901 used so successfully in winning the FA Cup, Spurs the only non-League team ever to do so, was based on one of the inside-forwards, in fact himself from inside-right, dropping back at times to aid the fetch-and-carry of the ball to the other in the attack. He did it in conjunction with an existing Scottish-style centre-half as the team's attacking pivot and it was this same system that Chapman, when he went into management, was to use so successfully first at Northampton and then at Huddersfield. At the former he achieved promotion. At the latter it was two League Championships and an FA Cup.   

However, this methodology would come to an end at least for Chapman in 1925 with the change of the off-side rule to two players in advance of the forwards, rather than the previous three, effectively the 'keeper and the two full-backs. Ironically it was adoption the previous rule in Scotland, was done to increase the number of goals scored, worked for a season and so and then prompted a reaction that more or less eliminated any gains. And at the forefront of the reaction was none other than Chapman's new club, Arsenal.

The originator was said to be Charlie Buchan, the Highbury club's centre- cum inside-forward, who himself was a Diasporan Scot, London-born of Scots parents. The idea was on the face of it the replacement be it of the if not Scottish then Scots- or Welsh/English-derived centre-half with what continued to be called a centre-half but was actually a centre-back. Of course, the innovation was more complicated than simply name. It involved positional change. The new centre-back did not play in front of the half-backs behind the forwards but now between and in front of the full-backs and behind the half-backs. It meant tactical changes. Now for off-side both the full-backs and the centre-back needed to step up and not just one full-back. And the opposing centre-forward now had a direct marker and that marker also took over as the main clearance-header, be it against the No. 9 or in open-play. And it required physical change. The centre-back was to be not only robust but now above all tall. The Welsh/English concept of the centre-half as the strong-tackling, average height, mainly defensive middle of three across the middle of the park or the Scottish centre-half, medium or even small in height, who could tackle but above all could pass could both be consigned to the past. 2-3-5 and 2-2-1-5 had become 2-1-2-5, in the latter case most obviously The Cross, the attacking cross, replaced by a defensive one.

Except there was a problem. In the Welsh/English case part and in the Scottish case most of the link between defence and attack had been sacrificed and it took some time for Chapman to try to find a solution or rather solutions, both by going back to the John Cameron example. At first he required his inside-forwards, none other than Charlie Buchan and particularly Edinburgh-born Billy Blyth, who could play either inside-left of left-half, to do the fetch-and-carry. But both were aging, already into their thirties and it left a de facto forward-line of three, a centre-forward and two wingers in a 2-1-2-2-3. Then by 1930, whilst Blyth had been replaced by the equally left-sided Alex James and Buchan by another Diasporan Scot, David Jack and the wingers remained, the only real adjustment was in Jack Lambert in the No 9 shirt being both a centre- and an inside-forward, so with perhaps a little more sideways movement, even subtlety. 

In fact in the 1927 the Blyth/Buchan Arsenal would taste FA Cup defeat. And, whilst it was rectified with James and Jack in 1930, just two years later it would taste it once more. But this time there was perhaps an excuse. James was unavailable and the team had to be rejigged with Bob John brought in, left-sided but a half- or a full-back so defensive, and Cliff Bastin having to drop to provide the mid-field, attacking drive from the left-wing.

Yet whilst John actually scored it, or rather what we today would call mid-field, did not work. Newcastle hit two to win and that was the last occasion under Chapman that Arsenal had the chance to lift the trophy. But the loss was perhaps the spark for the next time the club reached Wembley. By then Chapman was two years passed and George Allison was manager. However, he was a media- not a football-man. The football side was run by the trainers, Tom Whittaker and Joe Shaw, with the chief-scout finding the players to fit. That scout was a Scot with a very distinguished playing past as an attacking left-half and FA Cups under his belt both on-field and as a manager. He was Peter McWilliam.

Thus Arsenal's 1936 Cup Final team would see four new players, two in defence, two in attack. Alex James was still there and captain and perhaps most interestingly Wilf Copping had come in and at left-half.  He had been recruited as a replacement for John in 1934 from five seasons at Leeds United, could also play Welsh/English centre-half and as a result became, I would argue, the key to what was perhaps Arsenal's best line-up of the era. The defensive cross was there and the right side of the attack was a standard winger and inside-forward. But the left-side of it was where much of the difference lay in the interaction between Copping, aging  James and the evergreen Cliff Bastin. Under pressure in a 2-1-2-1-2-2 Copping could sit, James could drop to cover the middle and Bastin come from the wing to inside-forward on conversion to attack to do the carrying. Equally in attack again Bastin in a 2-1-2-1-4 or even a 2-2-1 -1-4 could revert to outside-left, James to play-making inside-forward but still covering the left channel up and down and Copping to move across to cover the centre leaving Herbie Roberts at centre-back to remain permanently in place throughout, perhaps moving a little left to create a block four but without any thought of attack what so ever.

Thus Arsenal, with James at almost thirty-four and on creaking legs hardly The Ghost that a generation later and a decade younger John White would be, was able to maximise its pivot's effectiveness in the moment. But more importantly victory over Sheffield Utd. that day by a single, late goal marks as good a moment as any in the five seasons to that point that the final piece, centre-half to centre-back, half to back, can reasonably be said to have been not just tried but permanently inserted to be copied by many less successful others into the jig-saw that we call modern football.