This is similar to Hinamaturi in Japan. Hinamaturi traces its origins to an ancient Japanese custom that Hina dolls are set afloat to the sea. The dolls are supposedly taking the bad spirits or luck by being carried away in the sea.
Hitogata means a human body. So, women visit shrines or temples to purify bodies or minds by putting hitogata paper on the surface of pure water. While the hitogata paper is being carried away, they pray for good purification and the bright future.