Around 2,400 soldiers, as well as tanks, field guns and helicopters were deployed at training grounds in the foothills of the iconic mountain, about 80 kilometres west of Tokyo.
Airborne troops parachuted from planes, anti-aircraft cannon were fired and F2 fighter jets whizzed overhead in a display of force by one of the world's best-equipped militaries.
The drills are meant to prepare Japan's Self-Defence Forces to repel an attack on its remote islands.
"There are various issues and uncertain factors such as China's forceful attempt to change the status quo in the East and South China Sea areas, North Korea's promotion of ballistic missile development and nuclear weapons and Russia's display of its presence in the Far East," GSDF Chief of Staff General Koji Yamazaki said in a statement.
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"The severity of the security situation surrounding our country... Is increasing," he added.
Japan has deployed its Patriot missile defence system after North Korea threatened to fire ballistic missiles over the country towards Guam.
Separately, Japanese and US military personnel are currently conducting live-fire artillery training in the northern Japanese island of Hokkaido.