Xiangqi End Game Technique #1:
Usage of King to control the movement of opponent piece
As shown on the diagram 1, Red's pawn already stayed at opponent palace's centroid position. What need to be done by Red is to move his chariot to deliver the final kill.
However, Black has both of his cannons formation to block Red' chariot to deliver the check. Black's cannon can just follow the movement of Red's chaiot. For example if Red R7=6, C3=4, R6=1, C7=9. Both cannon is protecting each other.
Black need to find a trick to overcome this situation.
For below case, Red can utilize his King to control the movement of Black' cannon.
Red moves first
R7=6 C3=4 R6=4 C7=6
This is the trick. Red moved his king to File 6 to control the movemet of Black's cannon on his File 4. Diagram 2. As seen, Black cannon at File 4 is no more protecting cannon at File 6.
........... E3+1 R4+1 E1-3 R4+2 Checkmates. Diagram 3.