9. Perpetual threatening to checkmate is a draw. When one side
perpetually threaten to checkmate and the other side cannot
resolve the threatening to checkmate, or can only keep moving king
to avoid being checkmated, it is a draw. (See examples in Diagram
6, 7, 8, and 9)
Diagram 6: Red moves first
R2=3 m7+9
R3=2 m9-7
R2=3 m7+9
R3=2 m9-7
R2=3 ....
Explanation:
In Diagram 6, 7, and 8, Red keeps threatening to checkmate but
those moves are not checks. It is different than perpetual check
and if the moves keep repeating, it is a draw.
Diagram 7: Red moves first
N6+7 k6+1
N7-6 k6-1
N6+7 k6+1
N7-6 ....
Explanation:
In Diagram 6, 7, and 8, Red keeps threatening to checkmate but
those moves are not checks. It is different than perpetual check
and if the moves keep repeating, it is a draw.
Diagram 8: Red moves first
C7=3 c3=7
C3=7 C7=2
C3=8 c2=8
Explanation:
In Diagram 6, 7, and 8, Red keeps threatening to checkmate but
those moves are not checks. It is different than perpetual check
and if the moves keep repeating,
Diagram 9: Red move first
C7=5 c6=5
C5=2 c5=8
C2=5 C8=5
C5=2 C5=8
C2=5 ...
Explanation:
Red's C52 is threatening to checkmate and its C2=5 can be
followed by P4+1 k5=6 P3=4 k6=5 P4=5 k5=6 P5=4 which keep threatening
to checkmate. This example is "One threatening to checkmate and
one IMPLIED threatening to checkmate" and should be ruled as a
draw.