Hey all. I have had this knife for a while, but have been hesitant about sharpening it. The last chef I worked is for told me since it is a single edged knife it only get sharpened on one side. He showed me the shinogi line which is miniscule; not at all like a sushi knife. So just wondering how I can tell if this knife should only be sharpened on one edge or both? Cheers.