IDENTIFICATION PLZ: help determine what this gold/black pin is???

IDENTIFICATION PLZ: help determine what this gold/black pin is???

Hi there :)
hoping someone here can help me determine what this gold and black pin
is???

I found it in Tokyo, Japan in the trash, believe it or not :)
with some old coins from a variety of Asian countries...

It resembles the style of pins that would be attached
to a military hat or uniform...
it has a screw type back.

There's a lotus flower design I think at the base of the design,
with the kanji characters for the number one.
It has gold trim on the obverse and reverse with an inlaid black matte
background.
It is a perfect circle and is a bit smaller than an American or
Canadian one cent.

It may be Chinese or Japanese, not sure.

Hoping someone here with more expertise can help out... :)

here's a link to a detailed close-up picture I took of it...
* img251.imageshack.us/img251/6752/asianuniformpinpr4.jpg

Thanks so much,
Gino C.