Chiaki is Terry Jeffords' former girlfriend from when he spent his junior year of college abroad in Tokyo, Japan.
Throughout the Series
In Charges and Specs, Terry mentions his ex-girlfriend from when he did a semester abroad in Japan. They dated briefly however Chiaki breaks up with him, coldly apologizing to him, claiming she thought he knew it was just a fling. Terry tells her that he came to Japan to learn Japanese but all he learnt was heartbreak. According to Terry, he moped for weeks afterwards until his roommates show him how to vent his feelings by smashing plates.
Chiaki was shown to be quite cold towards Terry remaining unmoved when he is upset and she doesn't seem to feel sad about their breakup although she apologizes for the misunderstanding.
She and Terry dated briefly when he was in Japan. Terry was more invested in their relationship than she was as he was shown to be very upset over their breakup whereas she appeared uncaring, as to her it was simply a fling. She remains untouched when she tells him that he came to learn Japanese but all he learnt was heartbreak.