In response, the Kuki navy, a Nobunaga army's vassal, blocked the estuary of Kizu-gawa River (Osaka Prefecture) with around 300 ships but the Mori navy, outnumbering the enemy, burnt out ships of the Oda army using flaming arrows and horokudama bombs (A fire smolders inside this weapon and, when it hits a target, fire comes out and suddenly spreads.) and sent Hongan-ji Temple the supply after the complete victory (the first Naval Battle of Kizu-gawa River Estuary).
信長軍はすぐさま、配下の九鬼水軍など三百余艘で木津川(大阪府)河口を封じたが、毛利水軍は数の利を生かして火矢や焙烙玉（中に火がくすぶっており、目標に当たると中身が出て一気に燃え広がる武器）で信長軍の船を焼き払い、大勝して本願寺に兵糧・弾薬を届けた（第一次木津川口海戦）。