I've been having trouble with the author-date style for biblatex-chicago, used with the option "csmdate=both". I use this option to provide "origyear" for some sources, but not for all. The problem seems to occur when I have 2 sources with identical authors and dates but no origdates. The following explains the problem.

I've added 2 references with identical dates and authors, but different titles and so on. When I cite them, biblatex-chicago does not differentiate between them. Where I would expect "Test 1935a" and "Test 1935b" I get two "Test 1935" but two separate entries in the reference list.

Any help is greatly appreciated.

Minimal working example:




\newcommand{\mainfont}[0]{CMU Serif Roman}
\newcommand{\mainfontitalics}[0]{CMU Serif Italic}
\newcommand{\mainfontCJK}[0]{HAN NOM A}
\XeTeXlinebreaklocale "zh"
\XeTeXlinebreakskip = 0pt plus 1pt







Citing the following references:

    author = {Test, T.},
    title = {Random Title of Article One},
    journal = {Journal},
    volume = {20},
    number = {3},
    year = {1935},
    pages = {1--46}

    author = {Test, T.},
    title = {Random Title of Article Two},
    journal = {Journal},
    volume = {20},
    number = {4},
    year = {1935},
    pages = {50--70}

Replacing the "year" field with "date" makes no difference.

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1 Answer 1


No clue why, but the citation style invokes \clearfield{extrayear} before printing the year label even when origyear is unavailable. Under cmsdate=both you can avoid this by adding the following to your preamble.

% citations
    {\usebibmacro{cite:labelyear+extrayear}}% omit \clearfield{extrayear}
% bibliography
    {\usebibmacro{labelyear+extrayear}}% omit \clearfield{extrayear}

You should contact the biblatex-chicago author directly to resolve this issue.

  • Thank you! This gives me the disambiguating letters in the citation, but not in the bibliography, where I still get only "1935" for both citations. Is this how it appears for you too? I will contact the author of biblatex-chicago regarding this issue.
    – Mårten
    May 24, 2013 at 17:24
  • 1
    @Mårten I added a fix for the bibliography. Please feel free to post the "real" answer once you hear back from the style author.
    – Audrey
    May 24, 2013 at 17:47

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