
Timeline of World War II combatant states and leaders
The rules I used while making the chart:
A state qualifies only if it was sovereign or nominally sovereign and its own forces actually engaged enemy forces.
Puppet/client states can qualify; collaborationist occupation administrations do not.
Organized anti-partisan warfare counts as combat.
The forces doing the fighting must belong to or be controlled by the state itself.
Actual combat is the qualification test, but the bar starts at the state’s formal entry into the relevant war.
Declarations of war against states the country never actually fought do not affect its timeline.
The bar ends at the formal end of the war against the last enemy that state actually fought, unless the state surrenders, collapses, switches sides, or ceases to exist earlier.