Nobunaga with 35,000 and Ieyasu with… (1570) — the same event in Rai Sanyō and Ōta Gyūichi

Rai Sanyō: Nobunaga with 35,000 and Ieyasu with 5,000 met Azai Nagamasa (8,000) and Asakura Kagetake (15,000) at the Ane River and defeated them…

What each source says

Rai Sanyō, Nihon Gaishi · AD 1570 · 姊川

Nobunaga with 35,000 and Ieyasu with 5,000 met Azai Nagamasa (8,000) and Asakura Kagetake (15,000) at the Ane River and defeated them.

舍東取西。吾所願已。乃引兵而西。與景健夾姊川而陣。
Location: 권18 · 元龜元年 6월 단락

Ōta Gyūichi, Shinchō Kōki · AD 1570 · 姊川(姉川)

The Nobunaga-Ieyasu alliance met the Azai-Asakura army at the Ane River and defeated it. The original gives "over 1,100 principal men killed or captured" (about 1,100 heads).

六月廿八日 卯刻己寅へむかつて被及御一戰
Location: 巻三(八)

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