Cut the tomatoes into bite sized pieces. Julienne the shiso leaves.
Take the pit out of the umeboshi plum and finely chop into a paste. Mix the ume paste, bonito flakes, soy sauce and sugar together well.
Put the cut up tomatoes into the mixture from Step 2 and toss gently. Leave for a while to let the flavors penetrate (about 15 minutes). You can chill it in the refrigerator at the same time if you like.
When the tomato is well flavored, transfer to serving plates and top with the shredded shiso and it's done.
Users "Pikarumama"and "Sakkomama" taught me that it's delicious with cucumbers in the mix. Slice 1/2 a cucumber, rub with salt and add.
Story Behind this Recipe
I wanted to enjoy something refreshing and summer-like.
Don't mix too much in Step 2. (Mix just enough that the tomatoes aren't falling apart.) If you leave the mixed tomatoes for a while, the flavors will penetrate them. Tomatoes that are ripe but still firm will look nicer.