bǎo jiǎ
historical communal administrative and self-defence system created during the Song Dynasty and revived during the Republican Era, in which households are grouped in jia 甲[jia3] and jia are grouped in bao 保[bao3]
保
bǎo
to defend; to protect; to keep
甲
jiǎ
first of the ten Heavenly Stems 十天干[shi2 tian1 gan1]