Hajimari no Niina(2010)

Hajimari no Niina

11-year old Niina is special. This is because she has the memories of her past life as a girl named Chitose still intact. Among these memories is a promise with Chitose's boyfriend which Niina then decides to try and fulfill. But can she really?

(Source: Shoujo-Crusade)

Included one-shots:
Volume 1: Koi Baka.
Volume 4: Yasashii Tenohira, Machibito