However on May 11, on the day of the all-out attack in Hakodate, the shells fired by a warship of the former bakufu 'Banryu-maru' directly hit the ammunition storage on Choyo-maru and triggered a huge explosion.
しかし箱館総攻撃の5月11日、旧幕府軍艦「蟠龍丸」の砲弾が朝陽丸の火薬庫に直撃し大爆発を起こす。