Japan took gold in the team free event in front of a home crowd at the International Swimming Federation (FINA) Artistic Swimming World Series.
The hosts scored 93.0333 points at the Tokyo Tatsumi International Swimming Centre to earn their second victory of the competition.
Spain finished second with 89.2667, while Canada were third on 88.2000.
Olympic champions Svetlana Kolesnichenko and Svetlana Romashina triumphed in the duet free, building on their success at last week's season-opener in Kazan.
The Russian pair dominated with a score of 96.9333, with Japan's Yukiko Inui and Megumu Yoshida their nearest opponents on 94.2000.
Chinese sisters Jiang Wenwen and Jiang TingTing were third with 93.7667 points.
Russia had more success in the mixed duet free through Aleksandr Maltsev and Mayya Gurbanberdieva, who scored 93.5333 to top the podium.
The competition continues tomorrow with the highlight routine, free combination and solo free.