Arms and armor during the Three Kingdoms period.

Jan 2019
Southeast Asia
That is what I thought too.

It is true that the Shang-Zhou greave is the first leg armor found in China, however it is a lone example. The Wei or Jin Dynasty is the point where thigh and leg armor become standard in Chinese armor.

Do we have any consistent depiction of Eastern Han and Three Kingdom equipment especially armor?

I just found them suddenly having leg armor and tall standing collar during the Jin Dynasty.

Armor China Three Kingdom Wei or Jin Dynasty archer 2.jpg

Also where did the various polearm of the Han Dynasty go?

It seems they already what looks like a Guan Dao.

Weapon China Han Dynasty glaive 3.png