Conventional Warfare
-without nuclear weapons.
Using weaponry such as guns or knives etc. and non-nuclear bombs.
It has been used in every conflict in human history until World War Two when the United States of America invented, tested and then deployed the first Atomic Bomb (1,000 times more powerful than any bomb available at that time.)
to hasten the end of WWII and get rid of the need for a Japanese mainland invaison.