This is not my firsthand experience, but one of my friend's. You can tie the knife directly on a table by C-clamp, stand two or three supports on the tabel that holds a horizontal thin metal board with many holes in it to sustain the lansky hone.
Using one hole you can sharpen a few inches, then move the hone on to another hole to start to sharpen next part of the edge.
I hope some wise would evolve this system and enlighten me, and my friend with how to sharpen a large KHUKURI with a lansky.
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\(^o^)/ Mizutani Satoshi \(^o^)/