Btw, I need historical inputs of Sanguo era weapons, equipments etc. There are various sayings about the presence of the stirrup, etc. Inputs from Sanguo experts would be nice (not SGYY experts, but SGZ and real history experts).
The earliest depiction of a stirrup in a figurine dates from 302 at Changsha, and it was only a single stirrup for mounting the horse. I would infer that most, if not all stirrups used in the Three Kingdoms were of that type. In any case, most cavalry in the early part of that period would have had no stirrups at all.
Cavalry would also have been mostly unarmoured or lightly armoured, hence Yuan Shao's crossbowmen could defeat Gongsun Zan's cavalry charge at Jieqiao with a single volley at close range. Horse armour was rare in the Central Plains, and was gradually incorporated through contact with the Wuhuan and Xianbei. Yuan Shao supposedly had 300 armoured horses at Guandu, while Cao Cao had only 10. This was because of Yuan Shao's alliance with the Wuhuan. By the time of the Xianbei rebellion of Tufa Shujineng in Liangzhou (270s), Ma Long had to recruit a force of men who could draw extra strong crossbows using a waist belt, so that their bolts could penetrate the armour of the Xianbei. It is recorded in the Jin Shu that these Xianbei all wore iron armour, and to be more agile than them, Ma Long had his men wear rhino-hide armour. Ma Long had to make heavy use of covered wagons as strong-points against cavalry charges and horse-archers, arranged in the Eight Diagram Formation credited to Zhuge Liang. This shows that the Eight Diagram Formation (ba zhen tu) was one composed of a horse wagon laager for anti-cavalry purposes, and employed heavy crossbows.
Another important aspect of anti-cavalry warfare throughout this period is the Lujiao, or Deer's Antlers. These were a type of anti-cavalry obstacle made up of criss-crossed wooden stakes. Cavalry forces would often have to send infantry or scouts in to burn the enemy Lujiao before making their charge. Xiaohou Yuan was ambushed and killed at Mount Dingjun while leading his troops out to put out a fire set on one of his Lujiao.