https://en.wikipedia.org/wiki/One_thous ... ami_cranes
Thousand Origami Cranes (千羽鶴 Senbazuru) is a group of one thousand origami paper cranes (折鶴 orizuru) held together by strings. An ancient Japanese legend promises that anyone who folds a thousand origami cranes will be granted a wish by the gods. Some stories believe you are granted happiness and eternal good luck, instead of just one wish, such as long life or recovery from illness or injury. This makes them popular gifts for special friends and family. The crane in Japan is one of the mystical or holy creatures (others include the dragon and the tortoise) and is said to live for a thousand years: That is why 1000 cranes are made, one for each year. In some stories it is believed that the 1000 cranes must be completed within one year and they must all be made by the person who is to make the wish at the end.