The Wave Motion Gun (波動砲 hadō hō ) was a powerful weapon capable of destroying anything as large as Australia. Its energy comes from the wave motion engine, which is a large device that behaves as a high-power capacitor. This "capacitor" charges up the power input to the critical point of 120% at which point the person in charge of the firing mechanism releases the final safety lock and fires the weapon when ready. Due to the massive need of concentrated power, the "barrel" of the weapon is required to be long, and in the Yamato's case, the barrel is the whole ship from the engine to the firing gate. Light emitted from the cannon is so intensive that crew within the light range of the cannon must wear Anti-Shock/Flash goggles in addition of tinting the window.
In Yamato 2199, a detailed explanation and system diagram of the wave motion engine and the wave motion gun are shown. The wave motion gun's proper name is the "Dimensional Wave Motion Explosive Compression Emitter". The wave motion engine sits at the core of the ship's reactor unit, and provides power by expanding compactified higher dimensions that are curled up as Calabi-Yau manifolds. With the expansion of the higher dimensions, energy is released into the wave motion reactor into the gravity wave compression chambers and the tachyon particle oscillator control unit. A super-gravity wave is created and directed towards the muzzle of the wave motion gun, generating a stream of micro black holes. These micro black holes rapidly evaporate and have their mass-energy fully converted into Hawking radiation in the process, and that is the source of the wave motion gun's destructive capabilities.
The Wave Motion Gun comes in at least two types, the dispersal type which at a certain point spreads out and causes damage to enemy ships in its surrounding vicinity and the concentration type, a more common type it fires a beam straight forward from the bow.
The gun does have one flaw though: if it fires all six shots at once, the ship that it's mounted on will be destroyed. Though you can recalibrate it (see Yamato: Resurrection) it is still a risky move to fire all six shots at once.
More than one Wave Motion Gun can be mounted into the ship's design. For an example, the Andromeda-Class Battleships and its successor all have two Wave Motion Guns that receive its energy through one core. This allows a firepower equivalent or higher than the Yamato along with with more surface area hit with one shot.
The Wave Motion Gun, developed from the energy dispersed from the wave motion engine, was originally invented by the Iscandarians, a race which expanded throughout the galaxy and ruled with an iron fist, just as the Gamillians did.
- It should be noted that in the original series, the bridge windows do not have an auto-tinting feature.
- In a few battles sometime the crew of the Yamato does not wear Anti-Shock/Flash goggles.
- In one episode, "Artificial Sun" the Yamato crew does not wear Anti-Shock/Flash goggles when aiming the Wave Motion Gun at the Sun, but don it prior to firing. This is viewed as strange as the Sun is much brighter than the muzzle flash.
- The Wave Motion Gun cameos in the pilot episode of Megas XLR where the front of the Yamato comes out of megas and fires the gun.
- Dessler made his own version, called the Dessler Cannon. It's used in the finale of the first season, and in the movies.
- Though not mentioned in the original series, the 2199 remake stated that the Dessler Cannon is a variation of the Wave Motion Gun. Given that the color violet is a shorter wavelength than blue, the output of the weapon is likely more powerful than the Yamato's Wave Motion Gun due to denser energy particles. Appropriately, the Dessler Cannon has been shown to decimate an entire enemy fleet in one shot and in the remake, engulf a planet in flames and eventually destroy it.