In the Yamato 2202 storyline, Captain Susumu Kodai faces a "promise to seal the Wave-Motion Gun," struggling with the ethics of using such a horrific weapon despite Earth's desperate need for defense.
The weapon utilizes generated by the ship's Wave Motion Engine , technology provided to Earth by Iscandar.
In later series like Yamato 2199 , the weapon is shown to be so powerful it can penetrate the barrier between subspace and ordinary space. Strategic Significance
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Its power has been compared to that of a Death Star from Star Wars.