The 16 months that Antonio Conte has spent as manager of Chelsea has seen great evolution in the team's shape.
Last season began with the manager deploying an adventurous but foolhardy 4-2-4, which was followed by a brief return to the 4-2-3-1, which had been used by his predecessors dating back to Carlo Ancelotti. September 2016's radical switch to a back three then became Chelsea's staple as they romped away with the Premier League title.
The first few months of this season have had similarities with 12 months ago as a variety of systems have been used while personnel changed. In an ideal world, Conte would have simply stuck to his winning template but, with opponents learning how to exploit his 3-4-3 and the manager facing different challenges to the ones posed last campaign, he has been forced to experiment.
Tinkering is a term associated with previous Chelsea boss Claudio Ranieri, whose employed constant chopping and changing when it came to team selection. But though Conte has also frequently sought alternatives, those tweaks have largely affected formation.
The title defence kicked off with 3-4-3 but defeat to Burnley and the prospect of playing Tottenham away saw a switch to a previously unseen 3-5-2, with Willian playing just off Alvaro Morata. Despite beating Spurs 2-1, Chelsea went back to their preferred system for their next six matches before reverting to the extra man in midfield for games against Atletico Madrid and Manchester City, albeit with contrasting outcomes.
Games since the 1-0 home defeat to Man City have seen the manager alternate between the two alignments and the intervening period has seen an upturn in the team's fortunes with greater consistency in performances. The reason for that appears to be twofold.
Much of last season's success was founded upon the time afforded to Conte between games to teach his squad exactly how he wanted them to play. Introducing new systems is all well and good but, without practice and repetition, there will be little of substance to galvanize the team and imbue confidence to perform.
With European football filling up the midweek calendar this campaign, those opportunities have been sparse and time to simulate the various scenarios when playing with less width and a three-man midfield has been unavailable.
The teething problems witnessed when playing 3-5-2 in the Man City loss and home draw with Roma were unsurprising; two good sides simply unpicked a team still getting used to its new shape. As time has passed, though, Chelsea's players have become more comfortable with the formation's demands and each game has seen them acquire greater understanding of the subtle shift in roles.
Additionally, having almost a full squad to choose from has undeniably helped with Conte no longer having to shoehorn square pegs into round holes, such as David Luiz in midfield or Cesc Fabregas putting in a defensive shift.
N'Golo Kante's absence with a hamstring injury was immensely troublesome and, unsurprisingly, the French internatiuonal's recovery has seen Chelsea's performances improve. Moreover, Eden Hazard's return from a broken ankle has been little short of stunning, with his rehabilitation clearly aided by Conte's patience and reluctance to rush him back into first-team action.
Even Danny Drinkwater's availability has made life easier for Conte. The deadline-day signing from Leicester might not have the same aura as Kante or Hazard but squad depth is vital in a busy season. Drinkwater can fill gaps in his neat and tidy manner and he has enabled the manager to give preferred midfielders time off without standards noticeably slipping.
The upshot is that Conte has two productive systems to deploy with a certain degree of confidence. 3-4-3 continues to be utilized against teams that Chelsea expect to dominate. Admittedly, it failed in the 2-1 defeat to Crystal Palace -- its success is largely predicated on the presence of Kante, who was injured that day -- but, with the right personnel it remains potent, as seen in wins at Bournemouth and Qarabag.
3-5-2 now appears the go-to approach when facing higher-calibre opposition. Lessons seem to have been learnt from the difficulties against Man City and Roma, as evidenced by the narrow but convincing 1-0 win over Manchester United.
So it is all but guaranteed that Chelsea will line up in the same manner when they travel to Anfield on Saturday. In what is perhaps the formation's sternest test to date, the mission will be to negate Liverpool's dynamic strike force and hit on the break through Hazard and Morata. The final whistle will tell us just how much has been learned in recent weeks