Nevermind, I got it sorted out:

count(preceding::item) - count(ancestor::checklist/preceding::item) + 1

PB wrote:
> Hi, should be an easy question.  I have XML which looks like the
> following:
>
>
> <book>
>      <checklist>
>           <item>Item</item>
>           <item>Item</item>
>           <sub-checklist>
>                <item>Item</item>
>                <item>Item</item>
>                <item>Item</item>
>                <item>Item</item>
>          <sub-checklist>
>      </checklist>
>      <checklist>
>           <item>Item</item>
>           <item>Item</item>
>           <sub-checklist>
>                <item>Item</item>
>                <item>Item</item>
>                <item>Item</item>
>                <item>Item</item>
>          <sub-checklist>
>      </checklist>
> </book>
>
>
> What I would like is to find the XPath that would label each "Item"
> sequentially, but starting from 1 under each checklist.  So in the
> above example, I would like this output beside each item:
>
> 1, 2, 3, 4, 5, 6
> 1, 2, 3, 4, 5, 6
> 
> Any help would be much appreciated.
> 
> Kind regards