GM Hu Ronghua's Sandwiched Horse Defense Treatise Chapter 09
In Chapter 9, Black would choose to play P7+1 very early to deny Red the chance to play P3+1. However, this would be done at the expense of underdevelopment of the left flank. There are three boards in this chapter.
- Board 1: Red Rapid Central Pawn Attack Variation
- Board 2: Red adds pressure on Black's left flank very early (R2+8)
- Board 3: Black plays 57 Cannons
The relevant Youtube videos have been done and embedded below.
References:
1. 胡, 荣华. 夹炮屏风 反宫马布局研究. Hong Kong and Singapore : 香港业余象棋协会 新加坡北斗象棋研究会, 1983.