Riddle me this: set-piece defense an enigma for Leicester and Stoke

Back three or back four? One striker or two? Some philosophical football debates will never be settled because there is simply no one right answer. But part of the fun of sports is arguing about which answer works best in theory. Then every week these theories play out on the pitch, and one theory gains temporary bragging rights.

Except when it doesn't. This was the case in Leicester City's match versus Stoke City when it came to the age-old question of set-piece defending: zonal or man marking? Each was deployed in this match, man by Leicester, zonal by Stoke. And each surrendered a goal. For this weekend at least, both the argument and the match ended in a draw.

While the terms "zonal marking" and "man marking" are bandied about in nearly every match, what do those terms really mean? Is it just a matter of marking an area versus marking a specific person? The Foxes - Potters match provided a perfect platform for examining the philosophy, strategy, and implementation of both defenses. First up, in order of goals conceded, is Stoke City's zonal marking.

The premise of zonal marking is simple. Each defender is given a specific area to defend. If an offensive player comes into that area, he is the responsibility of the defender assigned to cover it. If all defenders do their jobs and cover their respective areas, there should be no openings the offense can exploit to attack.

Stoke deployed a zonal-marking system on Leicester's first goal. As seen above, there are nine Stoke defenders in the box to mark five Leicester players. The only Stoke defender marking a player is Erik Pieters (3), who is defending Shinji Okazaki directly in front of goal. Six of Stoke's players are looking left at corner taker Riyad Mahrez anticipating his delivery. Only Darren Fletcher (24) and Kurt Zouma (6) are surveying Leicester's formation.

The biggest problem with zonal marking is that defenders tend to watch the ball and not the players around them, which is exactly what Stoke's players are doing. This creates the problem, for the defense, of leaving players completely unmarked for shots on goal. This is exactly how Vicente Iborra found himself before giving the Foxes the lead.

Openings as wide as the one afforded Iborra are what zonal detractors point to when arguing in favor of man marking on set pieces. Stick to the player you're assigned to defend, the theory goes, and there will be no open shots. As Stoke showed later in this same match, however, the man-marking theory also has its problems when it is actually put into practice.

Contrast the nine Stoke defenders seen earlier clearly playing a set position with the six Leicester defenders seen tightly grouped above. Each Foxes player is within one yard of his Stoke counterpart that is in the box. Even perimeter defenders Kelechi Iheanacho (8) and Demarai Gray (7) are near the Stoke players they are tasked with defending. With a Fox nearly on top of every Potter, no Stoke player should have any space to create a shot on goal. But proximity creates opportunity, as Stoke soon showed.

Notice how all the Stoke players in the box are bunched together. This is the offensive counter to a man-to-man defense. When defenders have a hard time getting to the man they are supposed to mark, this creates separation. Defenders have to not only fight through opposing players but sometimes their own teammates in order to mark offensive players making similar runs. Man marking also relies on communication, as defenders often have no choice but to switch off of their assigned man to take another player that has come open. This is precisely what happens on this set piece for Stoke.

In the picture of Leicester's defense above, find Wes Morgan (5). The Leicester player immediately to his left is Harry Maguire. The Stoke player immediately to his right is Crouch. Maguire is tasked with covering Crouch, but the Stoke player uses Morgan to pick Maguire off of him and create space. Christian Fuchs is then forced to leave his man, Maxim Choupo-Moting, to cover Crouch. Maguire tries to recover, but the confusion created by the pick, coupled with the extra inch in height advantage Crouch gains going from Maguire to Fuchs, is too much for the Foxes to overcome, and Stoke promptly equalize for the draw.

Which set-piece defense is better? In the first half few would have argued against the merits of man marking. But the second half showed the answer is not so clear cut, and one Stoke substitute took all of three minutes to carve Leicester's man-to-man defense to shreds. But isn't that the beauty of sport? Near certainties become mere probabilities and downright fallacies in a matter of minutes. And sometimes, like in today's match between Leicester City and Stoke City, the question simply remains unanswered.