The Woodcutter's accusation (situational irony)
The woodcutter at the end of the film accuses the commoner of being selfish, clenching him by the shirt after stealing the infant’s kimono. The irony is that the woodcutter himself is selfish, and the commoner tells him so as he knows that he did not give a truthful account of the events of the murder. Instead of telling what actually happened he selfishly chose not to get involved so he wouldn’t have to deal with the authorities.
Tajomaru's statement that women are weak (situational irony)
Tajomaru ironically makes this statement in the woodcutter's tale immediately before the samurai's wife rises up and castigates both men for failing to live up to the standards of honorable manhood. Tajomaru looks like a crestfallen boy as she mocks and rages at them, forcing them to duel against their will.
The samurai's release (situational irony)
In the samurai’s version of the story, Tajomaru cuts him free and leaves him. The irony is that he has no will to budge—even his hands remain behind his back though the ropes no longer hold him. Though he has been cut free, he has completely lost the motivation to go on living, and stabs himself with his wife's dagger moments later.
The woodcutter's understanding (situational irony)
The woodcutter wants to understand the tale without being truthful to the others about the extent of his own understanding. The opening line of the film, "I don't understand...," is rendered ironic by the fact that the woodcutter deliberately prevents the audience from accessing the most plausible account of the story until the end of the film. Though he claims to want to know, and his pursuit of the truth partly motivates the narrative, in the end we understand that it is his desire to avoid knowing, and to obfuscate the truth for others, that shape what says and does.
