Simple and refreshing hiyayakko is a quintessential summer dish in Japan. I can understand why: it takes minutes to make, doesn't require the stove or the oven, and is one of the best ways to appreciate the subtle flavor of fresh tofu.
The dish is made by topping a small block of tofu with a drizzle of soy sauce and a sprinkling of chopped herbs, ginger or other toppings. Either firm or soft tofu can be used; firm is easier to pick up with chopsticks, but I like the smooth texture of kinugoshi (silken) tofu. Freshly-made tofu is especially good prepared this way.
Traditional toppings include grated ginger, bonito flakes, shredded shiso leaves, chopped green onion and sesame seeds, but the options are endless. Any topping that lends some flavor without completely masking the subtlety of tofu is fair game.
Hiyayakko (Japanese Cold Tofu)
Makes 2 servings
1 block of silken or firm tofu
2-3 teaspoons soy sauce
Toppings of your choice (chopped scallion, grated ginger, sesame seeds, etc.)
Drain the water from the tofu. Cut the block in half and, optionally, into ½-inch cubes. Put each serving in a small bowl and drizzle with 1 to 1 ½ teaspoons of soy sauce, or to taste. Pile on the toppings of your choice. Serve immediately.
Related: Ingredient Spotlight: Tofu
(Image: Flickr member [cipher] licensed under Creative Commons)
Martha Concrete Lam...

This really does work best with fresh tofu, nothing else tastes quite as good. I like to use green onion, ginger, toasted sesame oil, and Kimlan soy paste (sweeter, thicker than regular ol' soy sauce).
Growing up in Hawaii this was always a delicious snack. We used fresh grated ginger, green onions and soy sauce (Aloha Brand). Adding sesame oil and seeds sounds wonderful too! I want to run out the store and get some tofu right now!
I like to add a little chili and sesame oil to the mix too as well as toasted black sesame seeds and crushed peanuts. It is so so so good.
I thought there was a special kind of tofu that works well for this dish--not just any old tofu will do, not silken. Does anyone know the name of it? You have to buy it in a Japanese market because I have not seen it at Whole Foods or even at a Chinese supermarket. But I could be wrong!
@Mimi Wan, as kittystockings mentioned, fresh tofu really tastes the best eaten this way, but in Japan store-bought silken tofu is regularly used if fresh isn't available. In general, the more expensive the better!
I use soy sauce, sesame oil, scallions and gomasio. Yum!
The dish will be much better if you make your own tofu, all the way from soy beans. It's surprisingly easy and much tastier. Here's a blog post on how: http://bottomupfood.wordpress.com/2011/06/15/homemade-tofu/
No, Anjali, "silken" tofu is not used for hiyayakko in Japan. No no no no no. This is one of my favorite dishes e-ver, but never with that soft stuff. Fresh tofu is pretty much the only way to go. If you can find it, this is the perfect dish to celebrate how wonderful tofu is. (And if I hadn't eaten my weekly allottment of soy for lunch in some atsuage, I'd be searching for fresh tofu for hiyayakko this weekend!)
This is how I eat it: http://cinnybear.wordpress.com/2010/06/03/green-eggs-and-tofu/ (not my blog, but exactly the way I make it myself)
yum! we did this with a hoisin/soy sauce mixture topped with scallions!
http://www.beyondthestoop.com/2011/08/watercress-and-beef.html
(article is about stir-fried watercress and beef, but at the end i show the tofu!)
cheers.
If using regular tofu, you can steam for a few minutes and then add toppings. Simple and delicious.