Silkworms hatched from eggs a few weeks earlier begin eating mulberry leaves in earnest now — voraciously enough that a mulberry field can visibly thin within days. In about a month they'll stop eating entirely and start spinning cocoons instead, the stage this kō is quietly building toward.
Sericulture in Japan runs back through the Edo period, but its real economic weight came later: from the Taishō era through the early Shōwa years, raw silk (生糸) was Japan's single largest export, produced by machine-reeling mills across the country that turned this exact seasonal cycle into a national industry.
Moving into its best season, firm and mild enough to eat raw as tataki or sashimi as well as grilled.
The main harvest is only just beginning in Yamagata's famous orchards — full Satonishiki season is still a few weeks off, but the earliest fruit starts reaching markets now.
Coming properly into season, at its crispest and least bitter right at the start of a long summer run.
The plant's flower stalk, cut before it blooms so the bulb below keeps growing — a mild, slightly garlicky vegetable in its own right rather than a byproduct.
Suzuran's small white bells are prized for their scent far out of proportion to their size, but every part of the plant is genuinely toxic if eaten — a reminder that a flower being delicate to look at says nothing about whether it's safe to handle carelessly.
Built in 1872 under French engineering guidance as part of the Meiji government's fukoku-kyōhei modernization drive, Tomioka Silk Mill in Gunma operated continuously for 115 years, until 1987, and became a UNESCO World Heritage Site in 2014. Its buildings still show the hybrid method used to construct them — Western-style wood-and-brick framing topped with ordinary Japanese roof tiles, one technology grafted directly onto another.
"Silkworm-eating" — A word borrowed directly from what's happening in the mulberry field right now — silkworms eating a leaf's edge inward in small, steady increments rather than all at once — extended to describe any slow, incremental encroachment, especially of territory or rights, taken one unremarkable bite at a time instead of in a single obvious act.
家蚕 (kaiko), the domesticated silkworm, exists nowhere in the wild — every population alive today depends entirely on human cultivation, a state reached through so many centuries of breeding purely for silk yield that the capacity to survive independently was bred out entirely, not lost by accident.
Silkworms eat from the edge inward in small increments — the exact behavior 蚕食 borrows its meaning from, visible in the leaf itself if you know to look for it.
Many local museums time hands-on silkworm-feeding demonstrations to this exact stage of the cycle, when the worms are active and easy to observe.
Feeding needs increase sharply through this stage — worth securing a reliable mulberry leaf supply a little ahead of actual need.
Neither holds its crispness particularly long once picked — good candidates for the next few meals rather than the back of the fridge.
The domesticated silkworm can no longer survive without people: it has wings but doesn't fly, no real defense against predators, and depends entirely on being fed, sheltered, and protected by the same species that breeds it for silk. Thousands of years of selection for yield rather than survival produced an animal that traded independence for guaranteed care, completely and irreversibly. Where in your own life have you made a similar trade — giving up some capacity to fend for yourself in exchange for something that reliably takes care of you instead — and does it still feel like a fair exchange?