[tetsusaiga]

I didn't really read it as him having an obsession with beating her—

It struck me more that this was his reckoning with the inevitable regression of his own cognition, in the context of comparison to the developing cognition of his daughter. Like racing the clock even if you have competitors on the track.

Sure, there was some disconcert over the fact he was "getting lapped" and he knew it, but I think that realistically we'd all feel that way at least a little. Even if it was our kid. Not because we're jealous of them, but rather because they are forcing us to face our own decline.

Not that I am necessarily correct. Just a thought.