Hailing from England (as evidenced by her occasional penchant for anything with a Union Flag), Yotsuba fancies herself a detective à la Sherlock Holmes. She can often be found with either a digital camera or a magnifying glass in hand, trying to spy on her brother. In the magazine stories and mini-novels, Yotsuba owns an unnamed talking toucan (not surprisingly, it can only say "checki" and "Ani-chama"). She refers to herself in the third-person and is fond of using the catchphrase, "Checky!" (チェキ! Cheki?). In the first Sister Princess anime, Yotsuba does not have a pet, but owns a toy bird aptly named "Watson", who she keeps in a cage like a real bird.She addresses her brother as Ani-chama (兄チャマ?), which is a childish address similar to Kaho's, but laced with a British accent. In English, she calls him "Brother Dearest". She celebrates her birthday on June 21, is a Gemini, and is 149 cm (about 4' 11") tall.