Why is this World Cup producing so many set-piece goals?

Group H of the World Cup kicked off on Tuesday with Colombia facing Japan, and it's fair to say things didn't pan out as many were expecting.

Related - Group of Life: Why Group H is the World Cup's most intriguing quartet

After Los Cafeteros midfielder Carlos Sanchez was sent off with just three minutes played, goals from Shinji Kagawa and Yuya Osako either side of Juan Fernando Quintero's crafty free-kick saw the Samurai Blue get its campaign off to the perfect start.

All three goals in the game were scored from set pieces - one penalty, one direct free-kick, and one corner. As it stood after the final whistle, according to Opta, 20 of this competition's 35 goals have come from dead-ball situations, some 57 percent. (Poland later scored another in its 2-1 defeat to Senegal, to make it 21 from 37 across the first round of group games.) That stands in contrast to the total from the entire 2014 World Cup, which stood at 30 out of 171 - less than 18 percent.

The fact a clear minority of the goals scored so far in Russia have come from open play is undoubtedly a headline stat, but what has contributed to the continuing trend throughout the tournament's first week?

Welcome to the VARty

Of course, the introduction of VAR has had an effect, if only simply because more fouls are being called at this tournament, and thus presenting more direct scoring chances.

This was first made clear on Day 3 of the tournament, when a penalty was awarded to France (and converted by Antoine Griezmann) upon the consultation of VAR after it was not initially called on the field. Two days later, Sweden and Andreas Granqvist profited from another video review which yielded a spot-kick.

Both were correct decisions, and with - theoretically - "clear and obvious" decisions no longer going uncalled, the number of penalty and edge-of-the-box free-kick opportunities has increased accordingly.

A load of balls

In 2010, you may remember, there was considerable controversy over the Jabulani ball used in South Africa, which was criticised for unpredictable movement in flight and for heavily favouring strikers over goalkeepers. Well, before this year's tournament, several top-class stoppers raised concerns about the official ball being used in Russia, too.

"I bet you as much as you like that we'll see at least 35 goals from long range, because it's impossible to work out," Spain goalkeeper Pepe Reina said in March. "And it's covered in a plastic film that makes it difficult to hold on to. Goalkeepers are going to have a lot of problems with this ball."

Meanwhile, Germany's Marc-Andre ter Stegen said: "The ball could be better; it moves a lot. But I think we're just going to have to get used to working with it."

But, while goalkeepers expressed worry, something that has been notable about the high number of dead-ball goals has been that, arguably, none have come as the direct result of a 'keeper badly misjudging the flight of the ball or being caught in no-man's land, and there has been nowhere near the level of furor over the match ball as there was in 2010, when it was clearly an issue for several players.

Back to basics?

Another factor may be the style of play and, possibly, the specific match-ups we have seen thus far. Favourites have failed to break down underdogs with a focus on defensive or midfield solidity (France versus Australia, Argentina versus Iceland, Brazil versus Switzerland), and games which have seen contrasting styles (Costa Rica versus Serbia, Sweden versus South Korea) have been settled from a stationary ball.

Croatia's 2-0 win over Nigeria was decided on not one but two set pieces, and coach Zlatko Dalic did not shy away from that fact.

"Corners and penalties are part and parcel of football," he told The Associated Press after the game. "It doesn't matter how you score; what matters is you score. There was some luck there, but we earned our luck. Of course we want to be more efficient on attack, but we are not going to split hairs about the way we scored."

Set pieces may not be the most aesthetically pleasing way to score - though there is obvious beauty to free-kicks like Cristiano Ronaldo's, Aleksandar Kolarov's, or, indeed, Quintero's - but pragmatism often outweighs flair in such high-stakes games. This may not prove a continuing trend throughout the tournament, but it's been a defining story of the first week.