37. When A's Rook and King are controlled by B's Rook and Cannon, A cannot use a Knight or Cannon to perpetually chase B's Rook. (See examples in Diagrams 94 through 96)

Diagram 94: Red (in Capital) moves first

K4-2 r67
K2+4 r76
K4-2 r67
K2+4 r76
K4-2 ....

.

.


Diagram 95: Red (in Capital) moves first

K4-2 r87
K2+4 r78
K4+2 r87
K2-1 r78
K1+2 ....

Explanation:
In Diagrams 94 and 95 the Red Knight is perpetually chasing the Black Rook. Red has to change or loses.


Diagram 96: Red (in Capital) moves first

C9-6 r6-1
C9+1 r6-1
C9+1 r6+2
C9-2 r6-1
C9+1 ....

Explanation:
Red's Cannon is perpetually chasing the Black Rook. Red is violating the rule.