Four-Player Chess/Checkmate patterns
All checkmate patterns that occur in regular chess can also occur in four-player chess. In four-player chess, however, players can combine forces to checkmate another player without that player being able to intervene, as he will have to wait for his turn. This makes for some interesting checkmates that are described in this section.
The fastest mate in the Teams variant takes only two moves. If Red and Yellow both open on the dark squares with h3 (or h4) and g12 (or g11), respectively, and Green also opens up the dark squared diagonals with l7 (or k7), then Green gets mated, if Blue does not intervene. Red plays Qxn8+ and Yellow supports the queen with Bm7#. This mate can easily be avoided, if Blue keeps a check on Yellow in hand.
This is a three-move mate in the Teams variant. Red opens with h3 (or h4), Yellow plays h11 and Green plays l7 (or k7). Then Red captures on n8 and Yellow plays Qh12. Green is in check and has to recapture the queen, but then Yellow mates with Qxn6#, if Blue does not intervene. Just like Fool's mate, this mate can easily be avoided, if Blue keeps a check on Yellow in hand. It can be in other forms, but still with yellow queen on n6, green king on n8 and green figures on m8, m9 and n9.
Two queens double check mate
This is the most basic type of checkmate in four-player chess. The queens of two players both check an opponent's king while supporting each other.
Queen and knight double check mate
This is another common checkmate, in which the queen and knight both check the opponent's king while the knight supports the queen.