Solved: Filtering out all cards which do not have a certain tag

[BigMan]

My deck has in total 2406 notes. Each one should have a tag which starts with HSK. But I know, a lot of the notes do not have. Those I would like to find:

I add in the search field: tag:HSK*
Result: 1254 notes. Somehow what i had expected.

Now to see those, which are missing a HSK tag, I thought I could do this:
tag:-HSK*
Result: 0 notes … but it should be 2405-1254= ~1100 …

I would be very grateful for a hint, what I am doing wrong. Thanks in advance!

[Nick]

I believe the hyphen needs to go at the beginning. Does -tag:HSK* work?

[BigMan]

Yes. That works!
Great. Thanks for that!