Sailor Moon, originally translated as Pretty Soldier Sailor Moon and later as Pretty Guardian Sailor Moon) is a Japanese shōjo manga series written and illustrated by Naoko Takeuchi. It was originally serialized in Nakayoshi from 1991 to 1997; the 52 individual chapters were published in 18 tankōbon volumes. The series follows the adventures of a young schoolgirl named Usagi Tsukino as she transforms into the titular character to search for a magical artifact called the "Legendary Silver Crystal". During her journey, she leads a diverse group of comrades, the Sailor Soldiers—Sailor Guardians in later editions—as they battle against villains to prevent the theft of the Silver Crystal and the destruction of the Solar System.