The Moon Rabbit is often told around the harvest time (Chuseok) because it has to do with the MOON and the moon is known to be the fullest during that time!
The legend goes like this:
There once was a rabbit, fox, and monkey who always played together. One day, the Emperor wanted to test the animals' loyalty to him so he approached them as a beggar. He asked them each for something to eat. Fox brought him fish, money brought him some fruit, and the rabbit brought him back grass.
It wasn't the rabbit's fault, however, he wasn't big or strong enough to bring anything else SO as an offering, the rabbit lit the piece of grass on fire and threw itself into there so that the beggar would be able to eat the rabbit.
This act touched the emporers heart and he believed that this was the true meaning of a noble sacrifice. So as a sign of this, he placed the rabbit on the moon to guard it.
And the rabbit being placed there is the shape that you can see on the moon -- the craters.
Hope you enjoyed~~~~
