Thank you, that is exactly what I was looking for. I am still trying to figure out the photo side of things. I have a few hundred knives collected over the last 40 years so I am sure I have some interesting ones to share!Yamaotoko, welcome to the forums!
The "X" is a date code. In your case it indicates the blade was made in 1990,see table below.
Hope this helps.
Post a pic of your knife if you can, we all love pics here.