Rashomon, with Spoilers

I thought a lot about this movie, and the most singular thing I find is the way each person claims that he or she is the murderer. The most puzzling thing is which was the murder weapon. In the beginning I thought that the samurai's story had to be the most accurate - partly because the monk says something like it's unthinkable that a dead man would lie, and partly because it seemed the most psychologically realistic - guilt and despair seem to be the appropriate responses when you fail to protect your wife, and she loses a knife fight trying to free you, and she gets raped in front of your eyes - but then I remembered that, oh yeah men are assholes, so maybe it isn't so far-fetched that he'd become as self-righteous and loathing ("I'd sooner regret losing the horse than a dishonored wife like you") instead of, you know, sad or humiliated.

The Wacky Interpretation:
In an attempt to explain how the most bizarre and seemingly unmotivated aspects of the story would have worked their way into the different versions - ie the wife's version - I'd like to suggest that the wife was the murderer. She went crazy and killed her husband with the dagger, while the men were so ashamed of not fighting that they pretended to have executed the deed themselves through more honorable means (sword fight, suicide). The Woodcutter corroborates the sword fight story simply to conceal the fact that there ever was a dagger.

The Conservative Interpretation:
The greatest intersection occurs between the Woodcutter's and Tajomaru's versions. Tajomaru would be most committed to maintaining face as the reckless bandit. The Woodcutter would be most committed to pretending there was no dagger. Excepting those details which are subject to bias, we might reasonably determine that:
1. The wife incited a duel between Tajomaru and her husband.
2. Tajomaru killed the husband (consider that he has the least to benefit from claiming to be the murderer).
We might futher assume that:
3. The rape was actually consentual, and the wife considered running off with Tajomaru afterwards (a fact the wife would be anxious to conceal)
4. Tajomaru begged the samarai's wife to marry him (a fact Tajomaru would be anxious to conceal)
5. The husband responded by acting like a complete asshole (a fact the husband would be anxious to conceal).
6. The sword fight was clumsy (as per the Woodcutter's version).

The Murder Weapon?
Logically it makes most sense to think it was the sword. Why else would Tajomaru have been so surprised to be asked about the dagger? He must have genuinely forgotten it was there, because he would have sold it otherwise. On the other hand, the ghost's description of a passer-by stealing the knife out of his chest is one of the most striking moments in the movie. Furthermore, why would the samurai and his wife have invented this small detail? It's possible to think that they simply had to, because the rest of their stories have Tajomaru run away with both swords before the murder or suicide takes place. But the wife, at least, would have had to have assumed that the murder weapon was obvious - how could she have known that it wasn't still in the body when it was found, or that the wound was indeterminate? - and in any case it seems uncharacteristically circumspect to fabricate such small details. Then of course there is the Woodcutter, whose claim that the murder weapon was a sword is the most suspect of all.

Thus, I venture that it could plausibly have been either sword or dagger. If it was the sword, we can think of the Woodcutter's version of the fight without much editing. If it was the dagger, we might imagine that in a moment of confusion and clumsiness, Tajomaru grabbed the dagger and killed the samurai with it. He didn't think of selling it because he was too unwilling and/or distracted to pull it out of a dead man's chest...

Which means that the Woodcutter would be the sort of monster who would not only rob a dead man of some stuff lying nearby, but would go one outrage further in stripping the corpse itself. This I think is the most interesting interpretation. His crisis of conscience was more severe than the situation seemed to warrant.