You have read plenty about the players who could make the biggest impact at the World Cup, but what about the coaches? Who are some of the masterminds at the international level whose flexibility and tactical nous could make for some interesting results in Brazil?
Here are five to keep an eye on:
Jorge Sampaoli (Chile)
Marcelo Bielsa is gone, but his influence lingers. It means Chile could be the most interesting team tactically in Brazil. The constants should be a high-energy pressing game, a commitment to outnumbering the opposition in midfield and use of the flanks in attack. The variables include the system. In qualifying, Sampaoli switched between a back three and a back four, using variants of 3-4-3 and 4-3-3.
The most intriguing option at his disposal is to play 3-4-1-2 with a false nine at the tip of a midfield diamond. The two forwards who are certain to start, Alexis Sanchez and Eduardo Vargas, are accomplished wingers and they can split, leaving the space in between for an attacking midfielder -- Arturo Vidal, Jorge Valdivia or Matias Fernandez -- to break into. Chile ought to be able to unsettle opponents with their tactics even if group stage opponents Spain and the Netherlands are also capable of varying their plans to suit particular games.
Jose Pekerman (Colombia)
It is something of a South American hybrid. Colombia arrive for their first World Cup in 16 years under an Argentinian manager, Jose Pekerman, yet the formation they may play could be quintessentially Brazilian: 4-2-2-2. It is the shape Carlos Alberto Parreira ended up using in the victorious campaign in the 1994 World Cup, with twin holding midfielders but full-backs who attacked so much that they were in effect wing-backs, and two attacking, creative midfielders who would come infield off the flanks. In Colombia's case, they should be Juan Cuadrado and James Rodriguez, while the anchorman -- it was Edwin Valencia, but injury has ruled him out of the World Cup -- can drop in to make a back three when the full-backs raid forward.
Pekerman's is a system that can see his 4-2-2-2 at the start become what can be considered a 4-2-3-1, especially if Teofilo Gutierrez, the second striker, drops deeper to form a trio with Cuadrado and Rodriguez. However, it was also a system that brought the best from Radamel Falcao, who scored nine goals in qualifying, and without the injured striker, Pekerman has to decide who replaces the Monaco man and whether to play a more conventional 4-2-3-1, with Rodriguez supporting a lone front man.
Cesare Prandelli (Italy)
Second-guessing Cesare Prandelli is no simple task. The Italy manager could play three or four at the back, one or two in attack and virtually any formation. He began Euro 2012 with a midfielder, Daniele de Rossi, operating as a sweeper and ended the World Cup qualifying campaign playing 4-3-2-1. Italy's friendly results have been so poor in part because Prandelli has used games as extended tactical experiments, but perhaps his best system is the one he used for the majority of Euro 2012: 4-4-2 with a midfield diamond, allowing him to use four of his gifted central players. He has used a close cousin, 4-1-3-1-1, in recent warm-up games, with the intriguing possibility that, instead of using Andrea Pirlo as a playmaker, De Rossi will start behind the veteran.
Prandelli is one of the few Italy managers who hasn't been able to call upon a classic No. 10 -- Antonio Cassano comes closest of those on his current squad -- but that has made the manager more flexible. He lacks out-and-out wingers, which again allows him to switch shape more easily. If he wants to use three centre-backs, the Juventus trio of Andrea Barzagli, Leonardo Bonucci and Giorgio Chiellini have an understanding they formed at club level.
Louis van Gaal (Netherlands)
Either a 4-2-3-1 or a typically Dutch 4-3-3 served Louis van Gaal well in the Netherland's unbeaten qualifying campaign, when they scored 34 goals and only dropped two points. Yet, whether because of the absence of the injured central midfielder Kevin Strootman or because he lacks a high-class centre-back, the Manchester United manager changed tack in recent friendlies. He swapped to what he calls a 5-3-2, although in many respects it is a 3-4-2-1, with Wesley Sneijder allowed to operate as a No. 10 and Arjen Robben granted a freer role behind striker Robin van Persie.
It is a shape that allows Van Gaal to get his three most gifted players in positions where they can create and score goals, while relying on the other seven outfield players to keep them out. If that formula isn't working, he can revert to 4-2-3-1 or 4-3-3 with Jeremain Lens coming in to play as a winger.
Joachim Loew (Germany)
For Germany, read Spain. The system stays the shape, but the personnel results in radical differences in how it is implemented. The major issue for both is whether to start with a specialist striker or a false nine; the secondary question is whether proper wingers are employed to offer width, or whether creative talents converge in the centre.
The two extremes have been illustrated in recent friendlies. Germany began against Cameroon with Mario Goetze as a false nine, Mesut Ozil as a No. 10 and two inward-looking wingers in Thomas Mueller and Marco Reus. For much of the second half of the 6-1 win against Armenia, they had a target man in Miroslav Klose and wingers in Lukas Podolski and Andre Schuerrle, who may not be as technical but provide more pace and showed a greater willingness to run at defenders.
With Reus out injured, it depends which quartet from Toni Kroos (who can also play deeper in midfield), Mueller, Ozil, Goetze, Schuerrle, Podolski and Klose that Low selects in the four most advanced positions. Spain manager Vicente del Bosque has a similar dilemma: does he choose false nine Cesc Fabregas or genuine No. 9 Diego Costa?