Iran Press/ Asia: Hinata Miyazawa's two goals were separated by a Mina Tanaka strike before Jun Endo added a fourth.
Zambia goalkeeper Catherine Musonda was sent off for conceding a late penalty.
Her replacement Eunice Sakala saved Riko Ueki's penalty but was ruled to have come off her line, and the Japan striker slotted home the second effort.
Japan moves to the top of Group C, above Spain on goal difference.
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