Thanks for the replies.
I didn't know who the figure was and what the hitsu-ana were. I thought perhaps the empty hole had lost it's filling
Perhaps not in the best condition but most old tsuba's are unaffordable for me, so I'm quite happy I got one I like for 70 euro.
I did some research on restoration and I was able to remove the thick rust in the photo's with vinegar, a toothpick and cotton swab. Then I gave it a coat of Renaissance Wax.
The filled in hitsu-ana did become a shiny bright copper color from the vinegar and I was kind of disappointed because I lost the patina.
But to my surprise it went back to it's original dark color in about 8 days !
Here's the backside photo.