Narimasa and Toshiie came to blows by battling at Suemori Castle. Narimasa had laid siege to the Suemori castle 9 October with 15,000 men.
The passage describes a battle between Narimasa and Toshiie at Suemori Castle on October 9th, where Narimasa led an army of 15,000 soldiers to besiege the castle.