Choose a round, white lotus roots with holes that haven't turned black. One with evenly spaced holes is more attractive, and will look very pretty when cut into a flower shape.
Make a cut in between each hole (where the red lines are). Please refer to the red lines for the depth of each cut.
It looks like this from the side.
Make rounded cuts towards the vertical cuts (red) that you made before, following the yellow lines.
This is one that has been cut. The cut parts are the yellow parts.
Next, cut along the blue dotted lines in a curve. This easier if you flip the lotus root over.
Done. Slice to your desired thickness, and put in a bowl of vinegar water to prevent it from discoloring.
You can simmer quickly in sweet vinegar sauce to make sweet vinegar lotus root, or cook in any way you like. If you add some yukari powder (dried red shiso leaf powder) to the hot sweet vinegar sauce the lotus root slices will turn pink.
Story Behind this Recipe
I decided to upload it so many people could give this a try. You can peel the lotus root or not, it's up to you. The peel comes off as you cut the flower shape out anyway, so I don't peel it beforehand.
I also have a blog post with big photos, so if it's hard to understand here please take a look over there (Japanese): http://ameblo.jp/aurora-dreams/entry-11120532259.html