Puzzle: Xiangqi Opening Trap: Central Cannon Double Headed Snake Variation

Puzzle

Xiangqi Opening Trap: Central Cannon Double Headed Snake Variation

The diagrams shown one the famous Xiangqi Opening Trap. Before reached to this position, the previous move for Red was P7+1 for double headed snake formation. Obviously, Red want to develop his horse in next move.

Therefore, Black replied with C2=3 (Diagram 1). In Black's plan, if Red H8+7, then Black can P3+1 and threaten Red horse directly.... and mostly can gain a crossed river pawn!

Now it is Red's turn, do you think Red still can play H8+7?

Diagram 1

The answer is YES for Red! As planned, Black replied with P3+1. So, what are the tricks here?

Refer to second Diagram 2, Red to move and gained advantages!

One of the variations shown at the bottom of this post.