The holding midfielder
In the last two games Steve Clarke has used a 4-3-3 formation that can easily become a 4-1-4-1 or 4-5-1 formation. This has been a notable change from the last few months which have seen Reading usually line up in a 4-4-2 formation.
At West Brom Clarke mostly used a 4-2-3-1 formation but there's no real natural player at the Madejski Stadium to play the attacking central midfielder role. There's also the issue that this Reading team is inferior to his West Brom team so it makes sense to use another central midfielder and in Nathaniel Chalobah Clarke has a natural candidate to play the important holding midfielder role.
The image below shows Reading's average positions against Blackburn, on the left, and Bournemouth. Against Blackburn the formation looks like a 4-3-3 but on Tuesday it looked more like a 4-1-4-1 formation.
There are three notable consistencies from both games: the high positions of the full backs (which are almost a given in modern football), Chalobah's position as the deepest midfielder and the high position of Reading's wingers (Obita's position against Bournemouth is slightly skewed by him moving to left back during the game).
The latter two are the most interesting in regard to our semi final against Arsenal and I will cover the wingers later on. The importance of Chalobah on Saturday is perhaps best shown by Arsenal's last game which was against Burnley. The Clarets used their usual 4-4-2 formation and it was noticeable how often their central midfielders, Scott Arfield and David Jones, were behind Arsenal's attacking play meaning the Gunners were able to control the space in front of Burnley's defence.
This is shown in the image below. There is a huge gap between Burnley's defence and midfield not only giving Arsenal lots of space but also a chance to outnumber their opponents.
Giving a team has good as Arsenal so much space to counter will only cause you problems. It is why Clarke has clearly been drumming into his midfield the need for a holding midfielder to always be in position. This is shown below during the Blackburn game when Alex Pearce is uncharacteristically dribbling the ball forward.
Despite his team being on the attack Chalobah is running backwards to take up a position just in front of his centre backs (whilst Garath McCleary's high position is also shown). Against Bournemouth I saw more than once Jem Karacan doing the same run, as Chalobah, on the odd occasion that the Chelsea loanee did venture forward.
The defensive role of the holding midfielder is clear: be in position to protect your defence and be another body in the way of the opposition's attack. He will also have an important role to play on the ball but that deserves a section of it own.
Anyone who watched Sky's coverage of Arsenal's home defeat to Monaco will remember the passionate criticism of the Gunners by Graeme Souness. The Scotsman argued that Arsenal's wide midfielders constant habit of cutting inside made them easy to play against.
I'm not sure we Reading fans would completely agree but as you would expect from a football legend he makes a good point. Below are two images which show the touches made by Arsenal's wide midfielders against Monaco and Burnley.
The top is the Monaco game with Alexis Sánchez on the left, and Danny Welbeck and Theo Walcott on the right. Only Walcott (in the red) really stays out wide. Sánchez drifted all over the pitch as did Welbeck in his hour out wide.
The picture for the Burnley game is very similar. Sánchez, on the left, again plays all over the pitch as did Aaron Ramsey.
This tendency to play through the midfield shows the sense in playing three central midfielders. As already mentioned, Chalobah will be sitting deep in front of the defence but it will also be important that the other two central midfielders never get too far from him.
The image below shows an Arsenal attack against Burnley. It is the perfect example of how narrow they attack. All five of their attacking players from their 4-1-4-1 formation are in the middle of the pitch. The picture also shows Burnley's central midfielders again having to make up ground, which again highlights the role that Chalobah will be playing.
The image below shows Reading defending with this system against Blackburn. Reading's three central midfielders are all in close proximity to each other. One drawback of having your midfield play deep and narrow is that it can leave your wingers and striker isolated on the counter attack.
I'm sure most Reading fans will recall moments during the games against Blackburn and Bournemouth when we struggled to get men in the box. It may be frustrating but this is a deliberate move and makes sense defensively.
"Don't get into them, don't f*** them up"
You always know when fans are getting restless and anxious when the chant of "get into them, f*** them up" gets an airing. It's stupid at the best of times but will be especially inappropriate on Saturday.
Arsenal are comfortably the best dribblers in the Premier League with 16.9 dribbles per game; Chelsea are second with 12.9. Against such opponents the last thing you want to be doing is running around and diving in like a headless chicken (especially as the Gunners also top the Premier League chart for set piece goals).
Instead, as I've already said, it's important to hold your position. This doesn't mean you have to sit deep the whole game but it does mean you should be compact when defending to avoid having to chase your opponent.
Clarke seems to have adopted such a tactic in his last game against Arsenal in October 2013 when his West Brom team managed a 1-1 draw at the Hawthorns. The graphic below shows Albion's interceptions (on the left) and tackles in the game.
During the game Albion only made four interceptions and not a single tackle in their own box. They also did not record a single block anywhere on the pitch. 11 of their interceptions are in the central area in front of their penalty area.
This suggests that when defending they got men behind the ball in central areas and stayed close to their opponents. You can't avoid having to make tackles or interceptions but you can avoid being taken out of the game and make it harder for your opponents.
Monaco did something very similar in their 3-1 win over Arsenal in the Champions League. Whilst they did make a huge number of tackles (53), only six were in the box. Their two central midfielders, Fabinho and Geoffrey Kondogbia, made 23 of those tackles but only one was out wide.
Reading's players will obviously have to make tackles but they have to be calculated ones and in the areas of the pitch where they're supposed to be defensively. In his autobiography Sir Alex Ferguson revealed his tactics when facing Arsenal: "We didn't need to win the ball against Arsenal, we needed to intercept it. You need good players who can intercept."
Ferguson instructed his players to "stay with the runner, intercept the pass, then counter-attack quickly". So during Arsenal's no doubt many spells of dominating possession on Saturday don't urge the Reading players to "get into them and f*** them up".
I first started thinking about this article watching Arsenal play Burnley on Match of the Day. The thing that struck me most from the highlights was the lack of support that Arsenal's full backs get from their wingers. The picture below shows this.
At the top of the picture we can see Nacho Monreal trying to get back to cover Danny Ings whilst Sánchez is just walking back meaning Burnley's right winger, George Boyd, has lots of space.
On the other flank, Ashley Barnes has cut inside and Ben Mee is bombing forward. Aaron Ramsey is tracking back but as a later highlight below shows he is not a natural defender. In this image Mee is one on one against Héctor Bellerín. He knocks the ball past him but Ramsey doesn't track his run. Sánchez meanwhile isn't even in the picture.
This lack of desire to track back was even more extreme against Monaco. The image below shows the touches made by Sánchez and Welbeck. Only two were further back than the centre circle meaning Monaco were able to get their wingers one on one against Arsenal's full backs.
I hadn't seen or read any description of the Monaco goals before finding these images so it came to no surprise to me when I did finally watch them that their second goal came from the Monaco left winger, Anthony Martial, being high up the pitch.
In fact for a game spent so much in Monaco's half there is one rather odd stat that sticks out. During the game Martial only touched the ball twice in Arsenal's half. This though wasn't because he was lazy, it was a deliberate tactic.
Rest on the ball
Maybe is the answer. Or perhaps the question should have been did Monaco copy Steve Clarke? In his first season against Arsenal, Clarke encouraged his defensive central midfielders to play the ball long.
That would seem to be a natural tactic if you want to play high wingers except you then risk constantly chasing the game and never giving yourself time to rest.
Clarke seemed to realise this in his second season and instead encouraged his defensive central midfielders to keep hold of the ball against the Gunners. This allows you to slow the pace of the game down and stop the opposition's momentum. Albion's two defensive central midfielders' pass success rate went from 82% in both games in the 2012/2013 season to 91% (on the right) the following season.
Where the passes are aimed has also changed. In the first season there were plenty of long hopeful balls through the middle. There were far less long balls in the game West Brom drew but when there were they were aimed out wide.
A similar picture emerges with the passing of Monaco's Fabinho and Kondogbia. They enjoyed a pass success rate of 91%. The long balls they attempted are nearly all out wide and there are also lots of safe sideways passing. The passing of Nathaniel Chalobah (on the right) for Reading against Blackburn is not too dissimilar (though not as successful because we're 18th in the Championship for a reason).
So don't be too surprised if Reading do enjoy some moments of possession at Wembley. It may also explain with Danny Williams injured why Hal Robson-Kanu has started the last two games in central midfield. He's better on the ball than Hope Akpan and less likely to play a Hollywood pass like Oliver Norwood.
Despite this long essay we all know that it doesn't matter what tactics Reading play, if Arsenal play well they will win. However, in Steve Clarke the Royals might finally have a manager who has the tactical nous to make things difficult for the Gunners.
In the past Reading managers have been far too idealistic or tactically naive meaning Arsenal have barely had to break sweat. Clarke's record of drawing his last two games against Arsenal is a glimmer of hope for Reading fans.
Statistics are from Squawka and WhoScored. Images are from BBC Match of the Day, Blackburn Rovers Official YouTube channel, Squawka and WhoScored.