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votive tablet; wooden tablet usu. filled out with a prayer and one's name and hung up at a shrine or temple; orig. picturing a horse, as a stand-in for a donation of a live horse
絵馬に願い事を書いた。
I wrote my wish on an ema.
神社に絵馬がたくさん並んでいる。
Many ema are lined up at the shrine.
受験合格を絵馬に願った。
I wished for exam success on an ema.