Not possible as part of the merge process. It would have to be done by
manipulation of the datasource. If it's an Access database, by means of a
query that uses the Left() function in an express; if it's Excel, use the
=Left() function, If it's a Word table, a macro that stepped through the
rows of the datasource, using the Left() function/

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Hope this helps
Doug Robbins - Word MVP
> Is it possible to include only the first 9 characters of
> the full document name as a merge field? i.e Document name
> is "ABCD-1234-Test document.doc" Merge field value should
> be "ABCD-1234".