Japanese miniature helmets WWII sake cups

Porcelain sake cups with military designs.
Most of them I have found online that explains the time line as WWII. They are also named helmet cups. The matching green cups have a square foot and embossed rising sun, can't find information on them. That's about all I know about them. More reading will be required.
small porcelain sake cups 2" across x 1 1/4" tall.