There are traps made of paperwork, bills, and cultural expectations and there are traps made of sand. In an effort to escape one for a few days, Niki Junpei finds himself caught in the other in 1964's The Woman in the Dunes (砂の女 "The Sand's Woman"), a beautiful film about the boundaries that shape human behaviour.
Junpei (Eiji Okada) is a schoolteacher and an amateur entomologist who takes three days off from his busy life in Tokyo to catch insects living in the sands of a remote desert located on the coast. He captures the little creatures and pins them to a board, the parallel to his own capture by the local villagers being rather obvious. When he misses the last bus home, he accepts an invitation to take a rope ladder down into a huge pit in the sand where a woman (Kyoko Kishida) lives alone.
He stays the night, marvelling how the woman, who is never named, spends all her days and nights fighting the sand--using an umbrella to keep sand off the food, constantly shovelling sand to keep it from burying the building, and putting sand into crates that are hauled up out of the pits by the villagers. It's a sort of surreal, sinister cottage industry--people living in pits contribute sand to a criminal organisation that then sells the sand under the table to construction companies who use it to build cheap, substandard buildings and bridges.
When he asks her how she can be a part of such a scheme, she shrugs and says it's not her concern. The world outside the pit is like another planet to her. She doesn't argue with Junpei when he points out the advantages of living outside a huge pit of sand, she's simply and very completely accepted the pit as her reality.
She loves Junpei, wanting to have sex with him right away--he wakes up on the first morning to find her sleeping naked a few feet away--but her love for him is entirely due to the fact that he's trapped in the pit with her. She has no interest in any other aspect of who he is--she listens with smiling indulgence when he talks about insects and she seems curious about Tokyo in the way one might be interested in celebrity gossip. But, really, she's content to accept whatever the pit provides.
She's not the first woman we see in the film--Junpei, before being captured by a villager played by Koji Mitsui (who I remember best as the gambler from Kurosawa's The Lower Depths), thinks about his wife while he relaxes and we see visions of her on the dunes.
A first time viewer might take her as the Sand Woman of the title. His thoughts beginning with a rumination on all the responsibilities of city life he concludes with the responsibilities "men and women" have to each other, saying they're "slaves to their fear of being cheated. In turn they dream up new certificates to prove their innocence."
The woman in the pit is the opposite in that she basically expects nothing from Junpei except to provide a warm, male body. In its references to unions and extorted labour, the film may be interpreted as a criticism of communism. But it's really not that specific--it's a much bigger story about a human compulsion to escape freedom.