“Football is full of variables, unlike many other sports. This unpredictability is a major reason why we love the game. Regardless of tactics, systems, and playing styles, we never truly know what will happen once the ball starts rolling. Set-piece situations reduce the number of variables applicable at that point in the game. Coaches and players can plan and rehearse these restarts more than they can do for any other elements of [the] game. Furthermore, penalty-kicks reduce these variables even further.”
Including for the above-mentioned reasons, penalties and penalty shootouts are indeed the aspect of football most widely studied, including outside the sports sphere, e.g. in game theory and behavioural economics. Much of the complexity and certainly the dynamism of the game are stripped away here, leaving one kicker and one goalkeeper to face each other in a pre-determined situation, viz. an eleven-meter spot kick.
Corner kicks include considerably more parameters than do penalty kicks. Yet, they are still much less complex and dynamic than any other situation in a football game. Obviously, as compared to regular play. But also relative to free kicks, as one can never be sure where exactly a free kick will arise, if it will. Corner kicks, in contrast, tend to appear at least once – and generally several times – per game both in favour and against any given team. Importantly, they are always taken from the exact same positions, i.e. either one of two corners, and thus are most true to the set-piece synonym of being a “standard situation”.
Where the mentioned book made me think was where it pointed out that decisions relating to how to defend against corner kicks, such as how many players to keep up front, if any, “often depend on the philosophy of the coach”. I have no doubt this is the case. The author seemed to insinuate, however, that there is no one way to do it that is better than another, i.e. that all approaches are equally valid. This kept nagging at me a bit, leading me to elaborate the below proposition that it probably pays to keep (quite) a number of players up front when defending against a corner. Reasons for doing so are the following:
- When you keep/call everyone back, even if you clear the ball, you are sure it will be regained by the opposition (unless the goalkeeper clutches it, or it goes out).
- Only if you commit players up field, you have a (real) chance of scoring on the counter-attack (note that keeping a player “up field” does not necessarily mean near the middle line, e.g. France’s positioning of Valbuena and Benzema just outside their own box, with an eye on a potential counter-attack, led to a goal from defending against a corner in their World Cup 2014 game against the Swiss.)
- You seem to reduce the opposition’s chances of scoring from the corner as the ratio of defenders over attackers tends to increase the more players you keep up front.
This final point is generally probably least well understood and calls for additional explanation. It hinges on the fact that the opposition will be inclined to keep a player back for each forward you keep up front (typically in addition to one, for safety, i.e. not to potentially be caught out in a “man-against-man” situation). If the defending side keeps no-one up front, (at least) one player of the attacking side tends to stay back when his team takes a corner; two players tend to stay back if one opponent is up front; three players if two opponents are up front, etc. The implications hereof are the following:
- If you, as the defensive side, keep everyone back, you are ten defenders. The opposition is likely to keep one defender back, plus their goalkeeper. They have one guy taking the corner, leaving eight players potentially in or near the box, involved in the attempt to score from the corner (note that including the taker, who may be involved in case of a short corner, as an attacking forward does not substantially change the below reasoning). This means ten defenders facing eight attackers, i.e. a ratio of 5:4, or 1.2 defenders per attacker.
- Now, say, instead, you keep two men up front. The opposition will probably respond by keeping three defenders back. So you have eight field players defending the corner. The opposition are committing three defenders and their goalkeeper to the defence. One guy takes the corner, leaving six players to get involved in the attack. Agreed, there is now comparatively more space for those to move into, facing eight instead of ten defenders, but the ratio of defenders vs. attackers is now 4:3, or 1.33 defenders per attacker. I argue that it is this relative room an attacker has that is decisive, rather than the absolute space.
If this is all so, why not keep, say, seven men up field? Following the above reasoning, this may induce the opponent to keep eight field players back, leaving just one man in the box, to be guarded by three defenders (leading to a ratio of 3:1, so three defenders for one attacker). It is, however, unlikely that the opposition will see a need to actually keep so many men back. Note that defending with “only” two against two on a possible counter-attack is very risky but, say, five against five, or even six against seven, not that risky. And, as my reasoning of committing players of the defensive team to the attack hinges on keeping the ratio up, it rests on the opposition committing (at least) one defender to each of your players additionally left up field. Also, if they decided to push forward, say all but a couple of their players, facing only three defenders, their chances of scoring from the corner suddenly become very high, meaning that the potential advantage of you having committed men up front will likely not materialise as no counter-attack could be started.
The “optimal” number of players to keep up field thus appears to critically depend on how many defenders the opponent is holding back in response to you keeping more men up front. As long as the opposition are to commit (at least) one defender to each additional player you commit to the counter-attack, it would appear to be the more the better! As football is essentially played against an opposition, the “optimal strategy”, unsurprisingly, appears to depend on the opposition’s behaviour. As I have attempted to show, this should, however, not trick one into believing there is no approach better or worse than another.
