The winner was announced on Sunday at the University of Warsaw Library, at the 30th edition of the award.
The book, published in 2025 by the Marginesy publishing house, also won the Nike Readers' Prize organised by the newspaper Gazeta Wyborcza, meaning that the jury and the public agreed on the winner.
The novel's hero is Koń, a historian in his forties from Warsaw, who leaves Poland to fight when Russia invades Ukraine in February 2022.
Among his ancestors are Poles killed in Volhynia.
The title refers to the frontline zone where the fighting takes place.
Jury chairman Witold Bereś said the book was awarded on its literary merits, not because of its subject.
He praised the novel's language, which he said was free of political correctness and created to describe this war.
"Null is a place where there is nothing, but there is resistance," Bereś said.
He added that the novel was also about loneliness in the face of technology.
"We root for the suffering Ukrainians, but we know that these drones may one day fly here and devour us," he said.
Accepting the prize, Twardoch called it his most important book.
He said it had no thesis and was not written to fight for any cause.
"I wrote it to tell the truth, because that is what literature is for," he said.
He added that he believed in Ukraine and supported it, but that "literature is something else" and operates beyond current events.
Twardoch is the author of more than a dozen novels and short-story collections, including Morfina (2012), Drach (2014), Król (2016; published in English as The King of Warsaw), Królestwo (2018), Pokora (2020) and Chołod (2022).
His books have sold more than a million copies.
The winner receives PLN 100,000 zloty (EUR 22,800) and a statuette by Polish sculptor Gustaw Zemla.
The prize, awarded since 1997, is one of the most important honours in contemporary Polish literature.
(ał)
Source: PAP