The irony of Machado de Assis is that of a narrator who speaks with politeness and lets the reader perceive something else beneath: the interest, the vanity, and the fear of losing one's place that move his characters. Rather than condemning openly, he exposes, and the reader is the one who judges.
In The Posthumous Memoirs of Brás Cubas, the book is dedicated to "the worm that first gnawed the cold flesh of my corpse." In chapter XVII, the narrator recounts that Marcela "loved me for fifteen months and eleven contos de réis; nothing less," and love acquires a price. In Quincas Borba, the philosopher sums up his doctrine as "to the victor, the potatoes," and the novel shows what that phrase costs those who hear it in good faith.
It also appears in the chronicles. In "Bons Dias!", of May 19, 1888, the narrator is a slaveholder who boasts of having freed a young man and goes on treating him with kicks: the target of the satire is the narrator, not the author.
Studies define literary irony as questioning. The ironic narrator doubles the point of view, that of the character involved in the scene and that of the narrator who observes it from afar, and so he can also laugh at himself.
On Clavis: The Posthumous Memoirs of Brás Cubas, Quincas Borba.