Yanyan Kokoyan: Kawaiku Naru Okusuri

Three-month-old twin kittens, Yanmaru and Cocomaru, are taken away from their mother and taken in by a calligraphy teacher, Utako... in the town where the famous rabbit, Sentarou, lives...!?

(Source: Akita Shoten, translated)

Note: Includes one extra chapter.