27. When a Rook is confined by a Cannon and cannot move away from
a line, the Rook's move within this line cannot be considered a
chase. Also an attack with a Rook on this confined Rook is not
considered a sacrifice. Therefore, the attacking Rook cannot
keep chasing the confined Rook. If one of the moves of the confined
Rook is protected, this Rook can be perpetually chased. A Knight or
a Cannon cannot perpetually chase a confined Rook, disregard whether
the confined Rook is protected or not. (See examples from Diagram
63 to 66)

Diagram 63: Red (in Capital) moves first
C8+3 r5+1

C8+1 r5-1

C8-2 r5+2

C8+3 r5-3

C8-1 r5+1

Explanation:
Since the Black Rook is confined to the center file, the Rook cannot
be considered as perpetually chasing the Red Cannon. If neither side
wants to change the move, this game is a draw.

Diagram 64: Red (in Capital) moves first
R8+4 r5+4

R8-4 r5-1

R8+1 r5+1

R8-1 r5-1

R8+1 ....

.

.

Diagram 65: Red (in Capital) moves first
R2+2 r6+1

R2-1 r6+1

R2-1 r6-1

R2+1 r6+1

R2-1 ....

Explanation:
In Diagrams 64 and 65, the Black Rook is confined by the Red Cannon
and cannot leave the fourth file. Therefore, the Red Rook is
perpetually chasing the Black Rook and that is a violation of the
rule.

Diagram 66: Red (in Capital) moves first
R32 r87

R23 r78

R32 r87

R23 r78

R32 ...

Explanation:
One of the Black Rook's moves is protected, therefore, Red Rook's
attack should not be considered perpetual chase. If neither side
changes, this game is a draw.