Warhammer Nippon concept fanart: Nippon Artillery

Mangonel: A mangonel is a small catapult used in siege warfare to launch projectiles over castle walls, wreaking havoc behind enemy defenses. Due to its small size and limited casting ability, the mangonel doesn't have the impact of a cannon, so instead of destroying a castle wall, it simply ignores them, hitting whatever is on the other side. The mangonel projectiles are small mud bombs, filled with gunpowder and placed in the bucket at the end. The fuse is then lit and the bomb is dropped in an arc over any obstacles. Hopefully, when the bombs hit the ground, they explode, spreading flames everywhere, scaring anyone nearby and setting them on fire.
Nippon Cannon: Nippon cannons are inferior imitations of old world siege weapons so they are slow to fire and relatively inaccurate. But this doesn't matter when the target is as large as a castle wall or a massive beast of war! Once in place, they have a long range and deal heavy damage to defensive structures.

You can learn more about the Nippon the Oni shogunate fan project here: https://www.worldanvil.com/w/warhammer-fan-concept3A-nippon-the-oni-shogunate-danilagi7