inwards with messages requesting the surrender of the occupants. By January 15, with no response from the besieged, Ieyasu began an incessant bombardment that had a mainly psychological effect to diminish the morale of the defenders. The stone bases of Japanese castles were invulnerable to the artillery of the era and the structure of the castle remained virtually undamaged.

Realizing that the defenses were extremely strong, Ieyasu tried to convince Sanada Yukimura to change sides. Yukimura, who felt a strong antipathy for Ieyasu, rejected