How to create a smart group selecting documents having no tags

I have been playing around with setting up various smart groups to help me identify imported items that should be classified, deleted etc. after recently importing 1000 + items into Devonthink. I’ve tried, but failed to find a way to set up a smart group to display items lacking tags. Can anyone suggest an approach?

This has been discussed many times on these forums.

Use Item is not Tagged.

very helpful