So, the New Republic has called us, and I quote, an "Empire of Darkness!" What fool thinks that they can just go and give out names like that? A Republican! Named Leia Organa Solo! We will make her suffer from what she has called this "great Empire," I look at each other and I think, "the best troops in this galaxy, by far." From today and on ward, we will push against the New Republic's borders!
—Galactic Empress Annabelle Nakamura to her Empire, and calling out Chief of State Leia Organa Solo
The Cold War, often at times called the Nakamura-Republic cold war, was a name given to the rising tensions between the Nakamura Empire and New Republic which started in 21 ABY whereas intelligence spies and agents of the Nakamura Empire had encountered a speech being given by Chief of State Leia Organa Solo and heard a part of it calling Anna's Empire an "Empire of Darkness!" This was what sparked the tensions between the two governments.
Days later after hearing about it from intelligence, Galactic Empress Annabelle Nakamura gave a speech to her military across her controlled territories, announcing the tensions and potential war between them and the New Republic Defense Forces.
In 26 ABY, the New Republic had issued defense fleets to various New Republic planets close to the borders of Nakamura Empire territories following the speech given by Empress Nakamura about pushing against the New Republic borders in the next few years.
In 29 ABY, Chief of State Leia Organa Solo was secretly transported to Mon Calamari by Jedi Master Luke Skywalker following the discovery of large Nakamura Empire fleets above planets controlled by them in the Core Worlds, including the largely defended Eclipse Station as well as various under-construction Executor II-class Star Dreadnoughts.
In 30 ABY, the Nakamura Empire had finally finished four Executor II-class Star Dreadnoughts, the Winter's Coming, Winter's Fall, Anakin J. Nakamura, and Marie Nakamura which saw their first battle in the Galactic War's Invasion of Coruscant as it was the New Republic's capital at the time.