Yaguchi (ヤグチ) is Yaguchi Mari's 1st solo photobook. The photobook was published by Wanibooks on February 7, 2002. The photography was done by Masashi Hashimoto.
The photobook's title is Mari's last name, Yaguchi.
The photobook shows Mari filled with plenty of life, showing off her cute and fun side. The photobook captures the many different faces of Mari from cute, to mischievous, to seldom, and to cheerful. It contains her wearing many differently designed and upbeat styles. She released this photobook after joining the sub group Minimoni.