The filmed explained

I read something interesting on youtube once:

To summarize what the commenter said: whole movie played in the guys head and he is really just in the bag remembering how he got in there and in the effort of comfort himself thinks about what would have happened if his son came home and killed her.

I don't know how this fits into the scene with the telephone and the bag, though i think it's possible that it was whoever her victim would be after him. This theory has as much weight as any other theory and does explain a lot about the ending if you look at it from that perspective.

"I loved you in Wall Street!"
- Hot Shots Part Deux

Thanks man for clearing out.
I thought it was a dream until ending scene. But when his son calls cops, I am lost again.

if you and your teacher are not japanese and do not speak japanese and do not live in japan today how could you come up with the conclusion:
"I think it's a reflection on the role of women in Japanese society and how they are viewed/treated, as well as the concept of the female as the monster put into question."

i assume you are talking about Americans,
women received right to vote 50 years later than any race/religion in united states didn't they?

ever heard a kitchen joke? where is the japanese version?

i will not go further

When was he rude to his son's girlfriend? I just watched the movie and I really don't think he treated the women around him badly, in fact he just seems to treat them normally. The only time is when he talks to his co-worker about finding a woman, I have to agree that and the audition didn't seem right.

I think the real monsters were the people who abused a little girl.

The only point of dreaming in this was when he was drugged with the scotch in his house. He is on the chair drinking, he falls backwards, has a dream, then wakes up and she is preparing for fun and games.

You may want to reassess just why you think your teacher is brilliant. A brilliant BS artist perhaps.

Thanks for making me feel justified in NOT labeling this film as "torture porn". While there are many Americans who can see the same elements your teacher and I did, there are many more who can't take the horror elements as anything but the reason the film was made.
I found it to be one of Miike's most "reasonable" films. I identified the misogyny and saw Aoyama as becoming less likable by the minute.
The film has a lot of Japanese cultural clues to the events that most Americans just don't get. Japanese literature and daily life are full of ghosts and minor deities. Although I have no idea of Miike's take on the story, I would think most Japanese people would see the Karmic side of the story, even if they were dismayed by the over the top violence.
I liked the way the woman was excising her own ghosts, however insane it was, and even if her self cure was also more punishment for her broken mind.
Its a horror movie. And a creepy intelligent one.

While the film surely explore those subjects of misogyny and the like, I also thought it conveyed a message of expectations/suffering/happiness, that you need the pain in parts of your life to truly enjoy the happy parts.

"you have to experience suffering to experience ultimate happiness, so push through the unhappy parts in your life and there will be considerable light in comparison"

and turned on it's axis

"don't be unhappy or do self-destructive things like hurting yourself, since what you have now is nothing compared to real suffering (tortured/abused by stepfather, tortured into being a cripple, murdered)"

At least that's what I take away from it.

And it also turned the "misogynist danger" on it's axis, since the misandrist (man hater) was way more dangerous. And that maybe guys shouldn't be so un-afraid of the date-rape scenario (or more likely date-assault if a woman was the perp).
After this film, several more films have explored this subject (The Red Riding Hood segment with anna paquin in Trick'r treat, the vampire/succubus (first) segment of V/H/S), when you root for a woman you consider be in a dangerous date/party position with a suspect male, only to have it turned upside down and having him be the one in danger and her being the villain.

So yeah, this film isn't completely without point.

Your points are as valid as they are intriguing, and I agree with them to quite an extent.

To be honest, I dived in to the film headfirst, being subjected to a lot of critique and reviews, most of them positive about it being masterful. I think I expected too much from the film and ended up being just a tad underwhelmed. I may have wanted something more from it. However, that being said, I'm still not too disappointed. For me, it's still quite a fascinating trip through the main characters' psyches.

What I find unbelievable, though, is that no one commented on two evident things portrayed quite constantly in the film:

One, Yoshikawa always wears white. This may be how Aoyama sees her; pure and innocent. Or, from her PoV, she may be pure and innocent, not having been loved the way she wants/wanted to; always having been forced upon. I guess, she might as well be still pure and innocent, but not in the conventional sense. I mean, she even wore white during the big torture scene. Oh, and what about the big coat she wears? It's red. Always red over white or just white. Red, for lust, jealousy, attraction, or anger and revenge. White, for innocence or purity. They come together even when they contradict each other.

Two, Yoshikawa has no ordinary wire, but a Piano Wire. An instrument Aoyama's late wife played throughout her life. Is this a form of guilty conscience? Does Aoyama feel like he's betraying his late wife, even after 7 years after her death, by falling in love with another woman? Let's say the last 20-40 minutes were indeed a dream sequence (I believe it was), so it's somewhat evident that he blames himself in some aspects of his life and how he's been completely delusional, falling for someone without paying attention to her woes and worries. He's been listening to what he wants to hear and seeing what he wishes to see instead of focusing on her troubles in the past and near present. Infatuated with the thought he may have found his ideal mate, he forgets to remember the crucial details which later emerge in his dreams and manifest as a guilt-ridden nightmare.

Three (not a part of the aforementioned yet holds importance), people mostly misunderstand the series of flashbacks regarding Aoyama's "adulteries" which are, in my opinion, mistakes of human nature; he did not sleep with a horde of women, or treat anyone badly (at least, not intentionally). There was a one-night stand with the Secretary, who clearly had feelings for him but I think he couldn't feel the same way either due to fear of losing someone else he cared about or betraying his wife; then was his son's Girlfriend, who he had no sexual relations with but ended up in his flashbacks maybe because he may have thought of her during some lonely night and ended up feeling guilty aboout; third was the Housekeeper, who showed a keen interest in him - dropping hints like "if you were my husband..." - and he definitely had gotten the clue except that she was married but, I sense, he did envision her in some sexual way for him to have her end up in his flashback.

It's always after I lose things that I realize how very significant the things I've lost are.