The term 精兵 jīng bīng today refers to élite troops or special forces.

However, would its use in historical military context refer to regular professional troops as opposed to conscripts who rotated between being soldiers and being farmers?

Or would it refer to really élite soldiers who underwent enhanced training or battle-hardened seasoned veterans?

I would think it would mean both, as having professional soldiers in an larger army with both regualr soldiers and concripts

and also elite troops who underwent special training and then forming a battlain of its own.

I'd think that the context depeneded on the different time span / army.

in general, it means the most well trained / armed troop in that particular army at the time.

In the Shiji and Zuozhuan, I have the impression that it just means "fine soldiers", or "best soldiers"... I don't think it would refer to specially trained units (or we'd get more descriptions of those), or be specific to professional soldiers (in most conscription countries, elite troops incorporate both pros and conscripts). Note also that in periods where wars tended to happen a lot, such as the warring states, the distinction between conscripts and professional troops probably mattered less than in our peacetime modern times...

Francois

精兵 did you quote it from baihua or from guwen?