Herring Kombu Roll and Conger Eel Kombu Roll

● Herring Kelp Rolls (Nishin Konbu-maki)

This is high-quality kombu, from Hokkaido. Use a scrub brush to remove the white powdery bloom on its surface. If that's left on, it clouds up the liquid during simmering and gives you a poor finished result. So much powder flies up that it turns your fingernails completely white, so it's not a task that's usually done right in the kitchen proper.

Reconstitute dried herring fillets (migaki-nishin) in rice-rinsing water. The herring used here isn't as hard as truly old-fashioned migaki-nishin, but it also isn't the soft, commercially available kind you often see these days. What matters with herring kelp rolls is that, once they're finished, the softness of the kombu and the herring feel unified. Kombu softens faster than herring does, so you have to make sure that by the time the herring has fully softened all the way through, the kombu hasn't dissolved.

Wrap the reconstituted herring in two sheets of kombu. Since the kombu will lengthen somewhat as it reconstitutes further, keep it a bit on the short side at this stage. Also, because the kombu will swell up, the rolls shouldn't be wrapped too loosely, or too tightly either — you need to roll it so that the kombu properly builds up its thickness later on, which is genuinely tricky to get right. When you've rolled it, keep the seam facing down.

Once it's wrapped in kombu, tie it up with kanpyō (dried gourd ribbon). Rub the kanpyō with salt, then rinse it and reconstitute it in water — really just a quick pass, just enough for the salt to spread evenly through it. Since the roll gets simmered and reconstituted further after tying, and then simmered again, it's better not to over-reconstitute the kanpyō at this stage. To avoid waste, use the kanpyō in its full uncut length rather than cutting it, and finish each tie with a secure knot. How many portions (kan) you get from a single kelp roll varies by restaurant, but here we get five portions as a rule, so when tying with kanpyō, you hold down one end, tie the middle first, then both ends, and then the sections in between. Always wrap it twice around at each tying point. The first wrap can be tied tightly, but the second wrap should be a bit looser — more like a soft, gentle wrap. If you tie both wraps tightly, once the kombu reconstitutes and swells up, it ends up looking like a boneless ham that's been strangled and it tears; but if you leave it completely loose instead, it falls apart while simmering. Always keep the knot on top — this is to keep the tied point from getting crushed under the pressure applied later. As I mentioned in the section on namasu, in the old days, even when building a house, the pillars were tied together with cord. The same idea applied to marriage, which ties one house to another — the act of tying together carried real importance.

Now you settle the rolls into the pot, and at this stage, you always leave gaps as you arrange them, changing the direction with each layer, stacking them three layers deep. They're arranged neatly, but the point is to make sure the simmering liquid can circulate well through the whole batch by the time it's fully cooked. You settle them so that the bottom of the pot is visible from any angle. Even with three layers, you want the same simmering liquid to reach both the bottom layer and the top layer equally. The top layer can be packed in fairly tightly, but for the bottom and middle layers, you leave a bit of a gap. You'll see once you've parboiled the rolls once — the kombu reconstitutes to a certain degree and gains some firmness, so you leave just enough spare room at that stage, imagining the state the kombu will be in once it's swollen. You give it that extra margin. That's exactly why stacking it more than four layers deep creates real problems.

Put this over heat and parboil it once, discarding the water. For the heat level, bring it just to the point right before boiling, lower the heat once there, and parboil it with the water discarded at that point. Herring, unlike conger eel, releases quite a lot of fat, so you parboil and discard the water 2 or 3 times. Once you've parboiled it down to a certain point, add sake, add dashi, and toward the finishing stage, add pickled plum (umeboshi) and put it through the reconstituting simmer. Use a drop lid (otoshibuta) and place a weight (omoshi) on top to apply a bit of pressure, but since this changes how much the kombu swells, adjusting this pressure is genuinely tricky. If you don't use a weight, it swells up too much, but it's not simply a matter of just putting any weight on it — traditionally, a weight equivalent to about one brick has served as a good baseline standard.

The exact time it takes to finish varies subtly depending on the condition of the kombu at that moment and how far along the herring has reconstituted. Just before it's fully done, the flavor is already about equal to what you'd get from a commercially sold kelp roll made with preservatives. But since we don't use any preservatives at all, we need to concentrate the flavor a little further still, in order to make it keep. The volume has increased quite a bit compared to when it was first settled into the pot, but the ideal outcome is for the very bottom and the very top of the pot to be cooked exactly the same way. The whole pot should finish at the same firmness and the same flavor throughout. When you first settled it into the pot, you pictured how far the simmering liquid would rise from the bottom once the kombu reconstituted, and left gaps accordingly; and likewise, in the step of tying it with kanpyō, you thought ahead to how thick it would become once fully cooked, and tied the kanpyō a bit on the loose side, remember. Now that it's thickened up and reached just the right firm state, none of the kanpyō ties have snapped anywhere — that's exactly because you settled it into the pot, and tied the kanpyō, while picturing in advance how much it would grow.

● Conger Eel Kelp Rolls (Anago Konbu-maki)

The conger eel is also all butterflied open right here. What goes inside the kelp roll varies from year to year, but as a basic rule, we always make the herring version, since it keeps well. Beyond that, depending on the year, we sometimes use meat, sometimes conger eel — the filling really does change every year in various ways. The reason for using conger eel is that, compared to migaki-nishin, which doesn't release much stock and finishes with a plain, simple flavor, conger eel has fat and releases stock right from the ingredient itself, so a higher proportion of younger guests will actually eat it; it's also easier to make, since it reconstitutes faster than herring does. Conger eel is in season in summer, but in winter it carries more fat, and you even see large ones like Matsushima conger eel show up. With a large conger eel, you do run into quite a few bones, but once it's made into a kelp roll, even the bones soften up.

This time we made two kinds of kelp roll, one with conger eel and one with herring, but herring is definitely the harder of the two to make. Conger eel has already been grilled once, and it almost never firms up too hard, so as a kelp roll it isn't especially difficult. Herring, though, has a tendency to firm up once seasoning is added, and since it's also been dried once beforehand, the seasoning doesn't easily penetrate all the way through. The more you simmer it, and the more sugar you add, the harder it gets — while kombu, conversely, gets softer the more you simmer it — so you really can't take your eyes off it; it's genuinely a difficult ingredient to work with. Different ingredients mean different fiber structures, and that changes how they reconstitute and how the seasoning, including the sugar, needs to be worked in. You want a firmness that's pleasant to eat, with the seasoning penetrated all the way through, and with the kombu still intact, not dissolved. One key point is balancing the kanpyō, the kombu, and whichever filling ingredient is used so that all three finish cooking at the same firmness in the end. Since it's a long-simmered preserve (nishime), it generally takes about three days of simmering, but you can't go beyond that. Past that point, it turns into essentially a different food — you lose both the flavor of the kombu and the flavor of the filling ingredient. Whether it's herring, conger eel, or even meat rolled inside, the seasoning differs in every case, but since osechi food isn't just about flavor but also about keeping quality, what matters within that three-day window is how thoroughly you work the seasoning all the way through so it will keep, and how much of the necessary seasoning you use to make that happen.