This formation is not as confusing as it looks.
It is a simple variation of 4-4-2 in which the second attacker plays just behind the main striker but ahead of the midfield.
If a player plays ahead of the midfield but behind the striker, it causes problems for the opposition because they find it hard to mark them.
The midfield already has four midfielders to mark and if a defender takes up the job, he will get pulled out of defence.
One player who has been an expert in this role for a few years was former Arsenal striker Dennis Bergkamp.
Bergkamp is virtually impossible to pick up - he goes into inside forward positions
Former England coach Don Howe
He is a master at standing still, which although it sounds stupid, actually finds him space as the play moves forward.
This formation allows a creative player a bit more freedom to operate. He has more options, to pass short or long, dribble, cut wide or bear down on goal.
If he fails to create an opening for himself, more often than not he will create goal scoring chances for others.
And the added advantage is that, if he creates something further forward, he can arrive late in the box to join the attack.