Total Recommendations: 6
Both have love polygons between friends, cute art and similar characters. Although the plot development is better in Koishitagari no Blue because it's longer.
Both girls, Yuki and Sumino, are very shy and thus have great difficulties in making friends. They learn how to socialize thanks to the boy they like.
Both the characters and the situations are similar. Two cute josei (nearly shoujo though) that you shouldn't miss if you like romance.
In both series magic girls from other worlds arrive at Earth to compete (collecting stones and hearts of boys respectively) in order to become the queen.
Both female main characters are torn between two brothers who are completely different from each other.
In both stories, at first, the main character is disliked, Sawako because of her scary appearance and Tanpopo because she's from the countryside. However these optimistic girls don't give up in making friends and finding love.