The Tokugawa family that chose a policy of reconciliation toward Toyotomi clan, but at the same time did not hesitate to prepare for war, ordered Kunitomo kaji (smithy in Kunitomo) to produce either odeppo (Japanese artilleries)/ozutsu (Japanese artilleries) as weapons for attacking a castle, and to cast ishibiya (Japanese artilleries) and ordered bronze artilleries/gunpowder/lead (materials of cannonballs) from England and Holland.
豊臣家に対し融和策をとる徳川家も戦の準備は怠らず、攻城兵器として国友鍛冶に大鉄砲・大筒の製作を命じ、他にも石火矢の鋳造、イギリスやオランダに対し青銅砲・焔硝・鉛（砲弾の材料）の注文を行っている。