Oyumi (siege)

The Oyumi is a siege weapon designed by Kaiu Mozi in the fifth century following the Battle of White Stag. Mozi was fascinated by gaijin crossbows and designed a larger version of the weapon for siege applications.

Function and Purpose
Oyumi were used to fire gigantic bolts at enemy armies. They were powerful, but proved to be ineffective against the Shadowlands and other enemies due to their slow reload times and need for ammunition. If an oyumi unit had to fall back, the oyumi was usually destroyed by the enemies or even used against the retreating Crab.

Variations
To address these weaknesses, Mozi spent his life refining the design. Mozi's first variant is known as the defensive oyumi. A large weapon mounted on a six-wheel frame, the defensive oyumi is normally operated by ten men. The defensive oyumi may be used by as little as four men, but aiming and reloading take at least three times as long.

A defensive oyumi fires a ten-foot long bolt and several smaller bolts in one shot. The large bolt may be attached by a chain to the oyumi and reeled in with a winch for reuse. It takes ten minutes to initially aim a defensive oyumi, and the better part of a minute to reload it.

The offensive oyumi was further modified to include a second or third bow, thus increasing firepower. The improved offensive oyumi can be operated by a single man, but the reload time of the weapon is greatly increased.

The ishiyumi is a dramatic variation on the oyumi. Instead of firing bolts, the ishiyumi uses a sling to hurl rocks at enemy structures. The ishiyumi is capable of destroying buildings.

Mozi's final modification on the oyumi is called the Rapid Dragon Engine. The Rapid Dragon Engine is a battery of up to ten oyumi linked together with a single firing mechanism. Each oyumi in the battery fires several arrows, allowing for dozens of arrows to be fired at once. The Rapid Dragon Engine takes a long time to reload, and is only used when reload time will not be a factor.

Views
Besides the Crab, most clans view oyumi as gaijin weapons and refuse to use them.