The 1979 Japan Open Tennis Championships, also known by its sponsorship name Hit-Union Japan Open Tennis Championships, was a combined men's and women's tennis tournament played on outdoor clay courts in Tokyo, Japan that was part of the Colgate Series and the Volvo Grand Prix circuit. The tournament was held from 22 October through 28 October 1979. Terry Moor (ninth-seeded) and Betsy Nagelsen won the singles titles.
Terry Moor defeated Pat Du Pré 3âÂÂ6, 7âÂÂ6, 6âÂÂ2
Betsy Nagelsen defeated Naoko Sato 6âÂÂ1, 3âÂÂ6, 6âÂÂ3
Colin Dibley / Pat Du Pré defeated Rod Frawley / Francisco González 3âÂÂ6, 6âÂÂ1, 6âÂÂ1
Betsy Nagelsen / Penny Johnson defeated Yu Li-Chiao / Chen Chuan 3âÂÂ6, 6âÂÂ4, 7âÂÂ5