This unique item is a Japanese "Lucky Frog" bottle opener keychain, traditionally used as a souvenir or a protective charm. It combines several layers of Japanese wordplay and symbolism to represent good fortune, safe travel, and financial prosperity.

The characters engraved on the frog's belly and the coin include:

御縁 (Go-en): Located on the frog's stomach, it translates to "Honorable Connection" or "Good Fate".

栓抜 (Sennuki): Also on the frog's stomach, this literally means "Bottle Opener".

五円 (Go-en): On the coin, this simply means "Five Yen".

無事かえる (Buji Kaeru): Often found on the back of these vintage items, meaning "Return Safely"

The back says:

日本国 (Nippon-koku): "Country of Japan".

昭和五十五年 (Shōwa Gojū-go Nen): This dates the coin design to the 55th year of the Shōwa era, which is 1980.

Symbolism: Real 5 yen coins (go-en) are considered lucky because the word sounds like "good connection" or "fate" (go-en).

Beyond its symbolic meaning, the "mouth" of the frog is designed as a functional bottle opener. These were popular as local souvenirs (omiyage) in Japan, often sold at shrines, hot springs, or tourist gift shops during the 1980s.