biber tries to treat CJK in .bib as ASCII, despite the file being saved in Unicode -> error in biblatex-chicago references

I'm trying to use a .bib that contains CJK characters for my document which uses biblatex-chicago and biber. However, biber writes out the bibliography in ascii when I run

biber <filename>.bcf


This prevents pdflatex to process the bibliography properly, and the references are garbled. My document is:

\documentclass{article}
\usepackage[american]{babel}
\usepackage[babel]{csquotes}
\usepackage[notes,isbn=false,backend=biber,bibencoding=utf8]{biblatex-chicago}
\begin{document}

Test\autocite{Xunisha2012}

\end{document}


and my .bib is:

@book{Xunisha2012,
Author = {{Xu Nisha}},
Publisher = {Payot},
Title = {Yi jiu qi qi nianjie de gaokao},
usere = {The 1977 session of the university entry examinations},
Year = {2013}}


Update

When I run biber with unicode:

biber -u -U try.bcf


I get nothing in the CJK fields instead of the garbled text from before; still no CJK output.

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Please have a look at How does one type Chinese in LaTeX? first. You did even not configure Chinese fonts in the TeX file. – Leo Liu Aug 11 '12 at 5:22
Thank you, that solved the problem! – Mårten Aug 11 '12 at 6:40

Thanks to Leo Liu's comment, the problem is now solved. When I write my file like this:

\documentclass{article}

\usepackage[fallback]{xeCJK}
\setmainfont{Gentium Plus}
\setCJKmainfont{SimSun}
\setCJKfallbackfamilyfont{\CJKrmdefault}{NanumMyeongjo}

%\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[notes,isbn=false,backend=biber,bibencoding=utf8]{biblatex-chicago}

\begin{document}

Test\autocite{Xunisha2012}

\end{document}


And run

xelatex


it works.

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I deleted the unnecessary lines in your answer. Now you can accept your own answer. – Leo Liu Aug 11 '12 at 8:07