Why do I see soldiers with the words "Feng", "Feng", "Anhui", "Zhi" and "Gui" on their shoulders in the national army?

"Feng" represents Feng Yuxiang, the representative of the northwest warlord.

"Feng" stands for Feng warlord, namely Zhang and Zhang Xueliang.

"Anhui" stands for Anhui warlord, namely Duan.

"Zhi" represents the direct warlord, namely the Cao Kun family.

"Gui" represents the warlords of the Gui clan, namely Bai Chongxi and Li Zongren.