Chinese/Mandarin SEO

I have two different web sites - They are exactly like each other but one is in english and one is in mandarin. I haven't been advertising for any of these but I get lots of visitors (mostly from Google) on the english version but I have *very* few visitors on the mandarin version. English version: [login to view URL] Mandarin version: [login to view URL] As far as I understand the mandarin version is accessible from anywhere in China. * I?d like to know how to increase the number of visitors on the mandarin version. Do I need some SEO modifications? * Is there any important web sites and indexes I should register?