らきすた or Lucky Star is the name of a Japanese manga, anime, and video game series. The manga was written by Kagami Yoshimizu. It was published in Kadokawa Shoten's Comptiq magazine since 2003 as comic strip manga. It was adapted into a 24-episode anime produced by Kyoto Animation in 2007, and a video game series was made through 2005 to 2009. It's mainly about the lives of four teenage girls who attend a Japanese high school.
Starting from the far left, there's Tsukasa Hiiragi, Ko