Here, as Field pieces, the white bishop and Queen do not pose a checking dispo-sition toward the black King. But, according to the rule of collusion, a major piece in the Field can check the King if the Spy of the same color moves to an adjacent Field square, or otherwise happens to stand

next to it. In the situation, left, by moving to d6, the Spy, bishop and Queen mate the King. Escape to d8 is not possible for the King, since the colluding Spy has power to check the King as well.