This is a bug in either Mavericks or in the upgrade to it.
I have a Japanese keyboard on this new mac pro(2013), and as soon as I upgraded to mavericks the keyboard mapping was wrong.

After the upgrade the only inout source was shown as Kotoeri, and although the key mapping displays correctly on the preferences screen, the @ had moved to Shift-2 when you type and the key to the right of p resulted in a ]

Adding a US keyboard and selecting this as the default input is a workaround...

and I notice that after adding the US keyboard it must be selected as the default input.
BUT after swapping betwen US and Kotoeri a few times the @ in the correct position seems to have stuck. I have never used a US keyboard on mac, so I dont know if the mapping displayed below is correct ?

I am sure there is some logic to this sequence, but since it's a very basic and unacceptable QA escape, Apple should just fix it urgently and stop wasting everyone's time.