Every year I have been saving the seeds from my Japanese tomato variety and they have done excellent each year. My technique is to inter- mix seeds from a large tomato off of 2-3 plants, and place the seeds on a paper napkin and let the seeds dry out and then place in a ziplock bag and label. Then in the early spring I sort through the seeds looking for the large and dark colored seeds, place the seeds on a moistened soft tissue, in a semi closed zip lock bag, and let the seeds germinate for a few days and then transplant the sprouts into a peat moss pellet that was soaked in warm water. Off I go for my next crop of tomatoes. I also use the same procedure on japanese varieties of cucumbers, bitter melon, melon, peppers) with good success each year.