It looks like those scratches have sharp edges and they are not that deep. It indicates that the scratches have developed at a late stage of polishing. Are you sure, that your strop is clean? If there are particles which are bigger in size than your stropping compound particles, scratches will follow. Is your stropping compound clean? Those unwanted particles can come from the earlier stages of polishing if the blade is not cleaned properly between the polishing stages. Even the surrounding air contains tons of particles which can make a stop dirty. Did you check how the edge was before stropping? Were those scratches there before stropping? You have to check and make sure, that all the scratches from the previous stage are removed.
In my experience coarse diamond stones often cause irregular deep scratches. It takes a lot of time to remove those deep scratches at the next stage of polishing. I´ve had better results with coarse ceramic stones. Your blade seems to be in really good shape and there is no need for coarse stones.
For a tiny bevel like that, I wouldn't use that many polishing stages. It is easy to remove the scratch pattern from the earlier stage. After 1000 grit stone you can jump to 3000-5000 grit stone and after that you can do the the final polishing with your polishing compound. Tiny steps save time if you have to polish a lot of steel like a long singe bevel Japanese sushi knife or the whole katana. For a big surface tiny steps like 1000,1500, 2000, 3000 etc. make sense, but for your knife it is just a waste of time and resources.
If I would polish the bevel I see in your picture, I would begin with a 3000-5000 grit ceramic stone and use it as long as I see any hints of those deeper scratches. After finishing with the fine stone, I would polish the edge with some polishing compound. If the scratches are deeper than what I see in the pictures, then I would use two different stones like 1000-2000 and 3000-6000 grit. It is essential to make sure, that everything is clean. The air, stones, strop, compound and blade itself have to be clean at every stage. Clean the blade before every stage. For example any particles from 1000 grit stone will cause problems at the next stage.
I have stopped using compound on leather for the final polishing. No matter how much I try to keep my leather strops clean, there always seem to be some unwanted particles which generate scratches. I've had much better results with paper. I just take a clean piece of paper, put a tiny amount of diamond paste on the paper and start stropping. I've used newsprint, printing paper and tissue paper. Tissue paper is the best for polishing because the unwanted bigger particles sink deep into the tissue. However, soft strop will produce a slightly convex edge. If you want a totally flat grind, hard paper is what you want to use.
Marttiini mirror
