There is a HJ knife for sale on Military Fighting Knives website.
Has the RZM 7/31 mark, and Eichenlaub mark.
I have never seen this one, but am not a expert or really knowledgeable about them.
Real or fake???
Ed

Hi Ed,

I was unable to log on for a couple of days on the site, that is why I reply that late...

It is always easier if you post a picture... but from your description, I can confirm that that is a existing combination of marks for a mottoed HJ-knife by August Merten.

Best regards,

Herman

Thank you Herman.
I have envied your HJ knives when you show them, a fine collection, thank you.
Ed