I think judging by the end of 282, that this fight is more of a draw than a loss for Musashi. Maybe even a loss for Ito. After all, Musashi isn't wounded, is he?
Yeah, but he was completely beaten and at Ittosai's mercy. The fact that Ittosai spared him, or that he didn't even need to cut him down to win in the first place, doesn't exactly speak well for Musashi as champion here. Though, this definitely gives the fight new perspective, and gives Musashi the opportunity to come out ahead. But, as far as the match itself goes, even Musashi admits Ittosai got the best of him. As things stand, just because Ittosai spared his life and didn't seek proper medical attention doesn't mean he somehow lost after the fact (I bet the old, more Takezo-like, Musashi could make that argument though, "that was his problem" =). Otherwise, did Denshichiro win his first bout with Musashi because Musashi collapsed from his wounds afterward, or what about after the seventy man battle, did Musashi lose again because he would have died had Matahatchi not again saved him?
I think the only way to make Musashi the "winner" is to redefine the terms of the match, or a complete referendum on the philosophy of the sword in general. As far as the Ittosai/old Musashi philosophy goes, Ittosai is clearly the winner, but perhaps by the Yagyu way, or new thinking by Musashi, there is no winner. It is a strong symbol that as Musashi reflects on all this, Ittosai falls, and Musashi seemingly rises.
Anyway, I'd like to see more between them, perhaps Musashi can finally convince Ittosai of the new age sword philosophy (and I want to know what happened to Ito's fingers).
If we are instead to consider what would have happened had Ito been using a real sword, then yes, Musashi would have lost, but if we were to assume both fighters were healthy, who knows.
All I know is who won at the time with what both brought to the table, "I entered, you fell." We'll see if that stands the test of time though.