To preserve vegetables, Japanese usually salt them (with or without fermentation) called "Tsukemono" 漬け物. Although Japanese use vinegar and rice vinegar is the best kind of vinegar I can think of, "true" pickling appears not to be traditionally done. More recently, however, quick pickles appear to have gained popularity. Since I had leftover Japanese cucumber and daikon, I decide to make a quick pickle. Also since my wife mentioned that she liked "pickled" boiled eggs, I also threw in some boiled quail eggs (from a can). (Pickled eggs are a Pennsylvania Dutch delicacy that my wife ate frequently as a child. They are hen eggs pickled and usually dyed red with the addition of beet juice to the pickling medium),
For color, I also added thin slices of carrot.
Recipe is rather simple. For the pickling liquid I used a Japanese sweet vinegar.
Sweet vinegar 甘酢:
Rice vinegar 300ml
Sugar 50g - 70g
Salt 1/2 tsp - 2 tsp
I placed the above ingredients in a small sauce pan, stirred to make sure the sugar and salt dissolved and let it come to gentle simmer for a few minutes. I let it cool down and kept it in the refrigerator. It lasts a long time (forever???). Depending on your taste, sugar and salt may need to be adjusted. In general, in hot summer, less sugar more salt and cold winter more sugar and less salt.
I added a few spices--thinly sliced dried Japanese whole red pepper (one, after hydrating to keep it from shattering when sliced), whole black pepper corns (4-6) and bay leaves (2) to make a pickling liquid. I did not add any water because liquid exudes from the vegetables and eventually dilutes the sweet vinegar anyway. I cut the Japanese cucumber into small bite sized chunks ("rangiri" 乱切; cut obliquely as you rotate the cucumber in about 1 inch length), daikon in half inch cubes, and carrot thinly sliced and, boiled quail eggs from a can.
After a few hours in the refrigerator, it was ready. It was nicely refreshing and crunchy. Perfect for hot summer. We ate this as a starter with sake. My wife particularly raved about the quail eggs. They were nice little bites with creamy yolks lightly vinegar in flavor.
P.S. Later I made this using American mini-cucumber. Although, the Japanese cucumber stayed crunchy even after several days in the vinegar, the American cucumber became a bit mushy. I may have to try this with an American pickling cucumber if I can find one.