| − | ''A long-range artillery secret weapon known as the "Type 91 Armor-Piercing Shell".<br>This type of ammunition will spin rapidly after exiting the gun's barrel, enter the water, and penetrate the target's armor below the waterline like a torpedo, crushing the hull of the ship.<br>The shell's shape enhances underwater penetration while also improving the range by decreasing air resistance.<br>Available for Battleship, Aviation Battleship, etc...
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