Since Japan is an archipelago, it would seem logical that there would be hundreds, if not thousands, of artisanal salt makers along its almost 30,000 kilometers of coastline.

However, a government-mandated salt monopoly shut down the making of salt from 1905 to 1997. The government decreed salt making to be its sole domain, partly to develop the domestic salt industry and partly to fund the Russo-Japanese War of 1904-05. So-called table salt (produced via a proprietary method of ion-exchange membrane electrodialysis) was the only salt available in Japan for most of the 20th century.

Fortunately, today there are many salt makers, both large and small, artisanal and not, as well as tourist destinations where you can experience the salt-making process yourself, such as at the Moshio Association in Hiroshima Prefecture. Moshioyaki, an ancient method dating back to the first half of the Kofun Period (220-552), is thought to be one of the oldest salt-making techniques in Japan.

Early references to the exact nature of this moshioyaki process are unclear, and slightly conflicting, but the process essentially used two core ingredients: dried hondawara seaweed and concentrated seawater.

Innovation: At Nami Hana Do, salt-maker Toshiki Kaba encloses his enden (saltpan) process in an elaborate greenhouse. | KENTA IZUMI

In 1982, remnants of pottery and stone used for salt making were discovered by Senshu Matsuura, president of the Moshio Association, at an archeological site and, in 1989, Matsuura replicated the method by gently simmering down sun-dried hondawara seaweed and concentrated seawater in an earthenware pot.

Now, a number of salt makers, located everywhere from islands in the Seto Inland Sea to Okinawa, produce modern versions of moshio salt by boiling down concentrated seawater in steel vats with a huge muslin bag full of sun-dried hondawara seaweed to extract varying grades of salt.

Salt making involves three crucial steps: harvesting seawater, concentrating seawater in an enden (saltpan) and slowly heating the concentrated seawater to gradually extract salt solids. Said seawater can be deep seawater, such as that pumped up by Hajime Nakamichi of Wajima no Kaien, or water pumped from the side of a pristine island inlet, such as for Nami Hana Do’s Goen salt. It can even arrive in Japan as inexpensive ballast on ships returning from Mexico or Australia.

Toshiki Kaba of Nami Hana Do moved to Shodoshima island almost a decade ago. Newly married, he announced to his wife, Kazumi, “Let’s go to a warm place.” The criteria for their new home: an old house, the sea and tangerine trees. They found all three on Shodoshima, and have lived on the island since.

Due to the virtual death of artisanal salt making, salt was no longer being produced on Shodoshima. Perceiving a gap in the market, Kaba launched himself into salt making a few years into life on the island. Initially, he set up his operation by the water’s edge and boiled seawater down in a large metal pot, but when he brought the salt to Kazumi she pronounced it “not tasty.” Galvanized by her negative reaction, and the desire to make a salt that she would like, Kaba researched better methods to produce his salt. Currently, he makes salt with a fascinating and visually stunning greenhouse-style rig for the enden.

Drip, drop: Calcium particles adhere to corrugated gutters during Kaba’s one- to two-week seawater concentration process. | KENTA IZUMI

According to Kaba, the enden process is not only crucial for evaporating the sea water, but also because it removes calcium deposits: Lingering calcium particles make salt feel dry since they do not dissolve in the mouth.

First, Kaba pumps seawater into large holding tanks and leaves it for three to five days to allow any solids to sink to the bottom of the tank. The top portion of the seawater is then pumped into fiberglass tanks located in a small greenhouse, where the water is circulated through a continuous shower system.

During this one- to two-week, 24-hour-a-day process, water trickles down fine mesh synthetic nets onto corrugated plastic gutters. As the water is cycled back into the shower system, calcium particles adhere to the gutters and the seawater evaporates down from its original 3 to 5 percent to a concentration of 10 percent.

Kaba then heats the now-concentrated seawater in a small shack below his house, where he has constructed a 2.5-meter-square brick base fitted with an iron trough of the same size. He builds a small, but raging, wood fire under the trough, which heats the saltwater enough to allow salt solids to gradually form.

As the seawater evaporates over a 24-hour period in the summer (or three days in winter), Kaba slowly adds additional warm concentrated seawater to the trough from a small holding basin above to increase the salt production per batch.

After the water has evaporated, Kaba mixes the early- and late-formed crystals together in a barrel, packs the resulting wet salt into muslin bags and leaves it to dry out naturally — if air-dried, Kaba says, the salt will become bitter.

It took several years, but now Kaba can barely keep up with demand for his Goen salt, despite producing 100 kilograms per month. It is heartwarming to see Kaba’s salt being used in all of the restaurants where I eat on Shodoshima — the feeling of cooperative community is palpable. It was because of that community spirit that I recently introduced the island to Netflix for the “Salt” episode of Samin Nosrat’s series, “Salt Fat Acid Heat.”

For that episode we learned about soy sauce at Yamaroku Shoyu, made miso with Kazumi and checked out Kaba’s salt- making set up. Regrettably, the Netflix crew had already visited a moshio operation on another island, so Kaba’s intriguing salt-making process and lovely mineral-rich salt did not make the final episode. But here, at last, I have told its story.

Tanoura 124, Shodoshimacho, Shozu-gun, Shodoshima, Kagawa 761-4424; 090-1281-8317 (Japanese only)

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KEYWORDS Salt, Shodoshima, moshioyaki