In Japanese they’re called omamori (お守り). They’re good luck charms that are said to have a god inside to keep you safe. There are a wide variety of omamori. There are traffic safety omamori, omamori that will allow a pregnant woman to have an easy child-birth, and omamori to help you with your studies, like this one.
Characters on front: 太宰府天満宮 (dazaifutenmangu) Dazaifutenmangu Official Webpage
Characters on back: 学業お守り – がくぎょうおまもり – gakugyou ommori (omamori for studies)
Sometimes shrines will be known to have especially powerful omamori of a specific type. This dazaifutenmangu which is in Kyusu (english wikipedia) is famous for its ability to improve luck in studying. It works. I’m sure.
You are supposed to return the omamori to the same shrine where you purchased it after one year. Otherwise, the charm will lose its effect.
I have only actually ever done that twice I believe… It’s hard when the temple is far away from your home!
Also, you are only supposed to have one omamori at one time. Otherwise, the gods will fight and none of them will work.
Remember these things… And good luck charms. Just like a four leaf clover.
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