In my Hartill catalog it's listed under Miscellaneous Items with the comment: "It is not clear if these pieces are trails, amulets, or just fanciful inventions" so I would put it under exonumia.
Yours has the designation 7.41a Obv.: Tempo Tsuho | Hyaku Mon Ban - Currency of Tempo | 100 Mon size Rev.: Sen Za Mint | type a - dotted border
It's classified as ER (extremely rare) but I can't say anything about the authenticity of your item.