When a friend of mine dragged two other friends from the States to Osaka to eat at the first restaurant I apprenticed at in Japan, they were prepared to pay 10,000 yen for the pleasure of eating the omakase, a several-course menu selected by the chef. What they were not ready for was the main dish: a big, steamed fish head, the traditional kotsu mushi (literally, “steamed bones”). Eyes widened and chopsticks were timidly taken up to probe the foreign matter presented on beautiful Bizen-yaki ceramic-ware. Later, the plates mysteriously returned to the dish sink devoid of anything but the fish bones, the famous nanatsu dogu, the bones shaped like seven different farmers’ tools found in the head of a tai.

After the meal, when questioned about their favorite course, all three praised the initially unfamiliar fish head. Beside the impeccable broth and the snow-white tender flesh of the wild sea bream from Akashi, what clinched the deal was the dipping sauce served alongside. Not the main component but surely the star of the arrangement was the ponzu sauce — the citrus-soy meld that has won over more than a few first-time washoku-ers.

Ponzu is a classic Japanese staple, but unfortunately fewer and fewer folks attempt to make this condiment at home. The availability of cheap mass-produced ponzu has surely contributed to this change. But the cost is far from prohibitive, and the process of putting the sauce together is actually very simple.

From its lexicography we can tell that ponzu has been around for a long time. Even Japanese food professionals, however, are unfamiliar with the true meaning of the word. The zu is vinegar, simple enough. Yet when I asked my chef what the pon of ponzu was he told me it was the sound that the top of the bottle makes when it flies off due to the buildup of pressure in the maturing ponzu concoction.

After a little bit of research, I found out that the word actually comes from the Dutch pon (English “punch”), referring to a drink made by blending brandy with some sort of fruit juice, usually citrus. Thus the sauce made from citrus juice is ponzu joyu, commonly abbreviated today as just ponzu.

The best citrus juice to use when making ponzu comes from yuzu (Japanese citron), daidai (Seville orange) or sudachi (small green citron), in this order, with the yuzu most delicate and expensive and the sudachi most commonly used. To make a quick ponzu sauce, combine one part shoyu (soy sauce) with three parts juice of any of these tart citrus or, in a pinch, even lemon juice. This simple sauce beats out store-bought ponzu any day. But for a truly delicious ponzu, try the following:

* * * * *

Ponzu joyu

A good complement to thinly sliced sashimi of mild white fish, steamed fish or traditional simmered one-pot dishes such as chirinabe or mizitaki, traditional ponzu is combined and let steep with no application of heat — the nama-awase (combined in a raw state) method. It needs to sit in a dark, cool place for at least a week before straining, and while it may be used immediately after that it is best with some additional maturing. Ponzu will keep practically forever if stored in a cool place.

360 cc citrus juice
240 cc koikuchi shoyu
70 cc mirin
30 cc tamari
1 tsp sake
10 g katsuobushi
5 g konbu

1) Combine ingredients in a nonreactive covered container (aluminum and copper are among the reactive metals). Let them steep for one or two weeks before straining out the katsuobushi and konbu.

2) For best results, let mature another several weeks before use. Keep a small portion in the refrigerator to be served chilled.

Kotsu mushi

The bold will be rewarded by the intense flavor of this simple dish. Get the fish heads, one half per person, at any fishmonger. The broth is a classic clear soup, sumashi, infused at the end with the liqueur used to steam the fish.

4 halves sea bream head
4 shiitake mushrooms
1 block momen tofu cut into 4 pieces
1 small bunch kikuna or other greens

2 cups dashi
usukuchi shoyu

ponzu sauce
finely sliced scallions
finely grated daikon

1) Sprinkle the fish heads with sake and lightly salt. Steam for five minutes. Add mushrooms and tofu to steamer dish and cook an additional five minutes.

2) Place dashi in a pot and season lightly with salt, a scant teaspoon of usukuchi shoyu and several drops of mirin. When the fish is steamed, add sake and fish liqueur to soup. Just before serving add greens to slightly cook.

3) Place steamed fish in individual soup plates and add mushrooms and tofu. Ladle over hot soup and greens.

4) Serve ponzu on the side in a small dish with chopped scallions and grated daikon.

In line with COVID-19 guidelines, the government is strongly requesting that residents and visitors exercise caution if they choose to visit bars, restaurants, music venues and other public spaces.