Occasionally Moyes opts for a defensive 1-5-4-1 or 1-3-4-2-1 formation, but his trademark at West Ham is a rigid 1-4-2-3-1 system.
In defense they often adopt a 1-4-4-2 shape that transitions into 1-4-4-1-1 with one of the offensive midfielders (Fornals, Benrahma, Bowen) assisting the striker (Antonio) in pressing. In attack the side defenders come out high overlapping the inverted wingers and creating an advantage under the rivals’ penalty area.
In the high and medium block West Ham United defend in a 1-4-4-2 formation, but leaves plenty of space between the first and second pressing lines. In this shape the wingers can press the rivals’ central defenders assisted by the full backs. This forces opponents to play through the center of the pitch, but there the three midfielders (Fornals, Soucek, Rice) are extremely effective in regaining possession of the ball.
However, as a team, West Ham spend most of their time defending in a low to medium block. The wingers line up in the central areas of the pitch to possibly push their rivals to the line after passes to the flanks and thus maintain a compact, narrow formation. The full backs help in the pressing by positioning themselves deeper but come forward to pressure the players entering the half-spaces.
The key player after losing the ball is the advanced striker (Antonio) whose pressing limits penetration in the centre and encourages rivals to play wide. The offensive four line up high while the other two central midfielders stay lower and are relatively inactive. When the opponent gets out from under pressure and passes into the Hammers’ half they adopt a compact 1-4-4-1-1 shape.
In attack they are keen on ball possession, but tend to adopt a direct approach where they look for the striker and use his ability to collect the ball to then engage players staying closer to goal. In counter-attacks this is particularly easy because, the striker pulls defenders, holds the ball and allows others to enter into the free space. This forward movement can also be used for passes into the half-space or on the wings.
The key role for ball possession is of course played by Declan Rice who is responsible for the tempo of play, but is also able to break down rivals’ lines with his exceptional progressive direct passing skills.
In a long positional attack they tend to adopt a 1-2-4-4 shape with a lot of rotation in the wide positions (Cresswell can play deeper, Coufal higher and then Bowen comes to the center) allowing them to create a natural 3 + 1 structure at the back with the central defenders creating passing options and protecting against possible rivals’ counter attacks.