Wack-i and Anchankia were already not too fond of each other, as Anchankia was sending supplies to Soviet Union and Wack-i was anti-soviet, and there was a border dispute on a small town called Smallake. And Wack-i were of Kazakh origin and Anchankians were of Russian origin, so they were kinda born to hate each other.
The Wack-i started a mass draft in suburban areas surrounding major cities, while Anchankia was convincing people from bordering cities (especially Smallake) to join their side.
The actual war was long, many soldiers were lost, blah blah. All that matters is that big battles happened. The Wack-i had better force and erased Anchankia from existence.
Anchankia was made into the Anchankia Region by demand of the Wack-i army, later to become the Fjord District. The Wack-i Annex and Accept Policy Law was heavily enforced on the area.
Effects and stuff on today:
Anchankians still mad up 15% of Wack-i Ethnicities. And the Wack-i still celebrate the day the war ended (October 19th, Anchankia-Wack-i Day), the day is also a tribute to the fallen of Anchankia.