EMA
絵馬
"horse picture"
An ema is a votive picture that is left at a Buddhist temple or Shinto shrine as an offering of supplication or thanks. Ema usually have an oblong shape and are made of wood.
The original ema were uniformly pictures of horses, hence the etymology of the word. (The first kanji character of the word ema, e 絵 ,means “picture.” The second character, ma 馬 , means horse.) The pictures were meant to take the place of a real horse. Today, however, an ema might contain the picture of any number of things: a tiger, a bird, etc. But the original name has persisted.
Ema are especially popular among students, who are constantly fretting over school entrance exams. Many leave ema at a temple or shrine just before an especially important test.