Samsin Halmoni is a very important and special grandma in Korean mythology. She is actually three grandmas in one! Samsin means "the three immortal beings" in Korean. These three grandmas each represent something different: heaven, earth, and water.
One of the grandmas is in charge of heaven and brings blessings from the sky, like rain and sunshine. The second grandma is in charge of the earth and helps plants grow, while keeping animals safe. The third grandma is responsible for water, like rivers and oceans, and helps people stay healthy and clean.
Korean people believe that Samsin Halmoni has a lot of power and can even predict the future! Many people pray to her for good luck and protection. So, if you ever hear people talk about Samsin Halmoni, just remember that she is a very important and special grandma who helps people in many different ways.