Knocked for … how many?

I heard a husband and wife disagree this week about the origin of a term that was new to me.  She had said that breaking her arm had really knocked her for six.

In context, it was easy to understand she meant that her accident had disrupted her routine and thrown her, as I might have said, off kilter.

Knowing she’d been born in England, I asked her if she thought being “knocked for six” was an English expression and she thought it might be since she’d known it all her life.  She seemed a bit puzzled that I hadn’t.

“I think it may come from cricket,” she said, since a ball hit out of the playing field in the air scores six runs.

Or maybe, her husband said, it comes from boxing: “You get knocked down and you lose unless you get up before the referee counts to six.”

She looked at him as if she wanted to knock him for six.  I refrained from saying that, where I come from at least, the referee counts 10 before holding up the other boxer’s glove to signify his (or her) victory.

Lucky for the husband, I think, that his wife’s arm isn’t yet healed.