Japanese cucumber are not all the same and the typical green spiky type are the most common. I purchased a bunch of cucumbers (a.k.a Kuri) at the organic market in Aoyama Tokyo, and decided to sour pickle them with a short cut. The recipe is simple: pickles, vinegar 100%, 40% water, 4% salt, garlic 1%, 1% mustard seeds, 0.5% black peppercorns, 0.5% green pepper corns, and a pinch of red peppers.
Before adding the brine, I did not heat the mixture or cure the pickles in the salt over night which is an option. I placed them into a fermenting container (below) and cranked down the cucumbers with some pressure, then placed them into the refrigerator. These containers are very useful in a fast style pickling. Otherwise a jar can be used for proper pickling, which is more suitable if you intend on keeping them for an extended period. In pickling with jars an anaerobic fermentation produces lactic acid, and the pickles ferment and change their color.