These have the same size as the "red" membership badges https://asiamedals.info/threads/red-members-badge-of-greater-japan-national-defense-womens-association.25437/
and sometimes could be found inside same cases.
The true reason of color scheme differences remains unclear.
1st...
greater japan national defense women's association
japan national defense women's association badge
national defense women's association badge
大日本国防婦人会会員徽章
大日本国防婦人会会員章
大日本国防婦人会徽章
大日本国防婦人会章