I have been trading FXI for quite some time but never understood the relationship between FXI and ^HSI.

What is the mathematical relationship as well as how FXI trades different than the mathematical.

Here's a one year chart but pretty much any length has substantially different movements.

http://finance.yahoo.com/q/bc?s=^HSI&t=1y&l=on&z=m&q=l&c=fxi

And of course I am not talking about the fact they trade at different times in the day, though that may have some effect.

I would greatly appreciate help here and/or pointing me in the right direction.

Thanks.