In a small saucepan over medium heat add the vinegar, water, sugar, and turmeric. Bring to a boil, stirring to dissolve the sugar. Remove from heat and allow it to cool.
Meanwhile, peel the daikon radish and slice into 1/4-inch thick rounds. (If your daikon is very large, slice the rounds into semicircles.) Place in a colander with salt and mix well. Place the colander over a bowl and let drain for 1 hour. Rinse the salt off with a couple of changes of water and dry the daikon well. Put into a sterilized glass jar. Pour the cooled brine through a coffee filter (or a cheesecloth lined strainer) into the jar to cover the radish slices. Refrigerate at least 4 hours, preferably overnight. Will keep for about 2 weeks.