This is a proper way to make a Hana Renkon (flower lotus root). The following video is in Japanese.
However, if you like to take a short cut… this is my quick method (it’s not as pretty though).
1. Cut lotus root into 2 inch length so it’s easy to work with.
2. Cut “V” shape between two holes and remove the v-shape part.
3. Slice into about 1/4 inch pieces.
4. Soak the lotus root in vinegar water (2 cups water + 1 tsp. vinegar) for 10 minutes and it’s ready to use.