雨水 (Usui) is the second of the twenty-four sekki, and its own name states its claim plainly: snow is expected to start falling as rain instead. 脉 (myaku) here means something like "pulse" or "vein," so 土脉 describes the ground itself as a living, circulating thing — 土脉潤起 pictures moisture spreading through soil the way blood moves through a vein, the frozen earth loosening and taking on water again after months locked solid. Japan's old farming almanacs used this kō as a genuine practical marker, a rough signal that field preparation could reasonably begin.
This particular kō has changed once already in the calendar's own history. The older Chinese-derived sequence this position, 獺魚を祭る ("the otter offers up fish" — an image of otters laying out their catch on a riverbank as though presenting an offering), was replaced when Shibukawa Shunkai and other Edo-period calendar scholars revised the seventy-two kō to better fit Japan's own climate and observed wildlife, swapping in this more directly agricultural image instead.
Coming into good season now, often simmered whole in a sweet soy broth (nitsuke).
At its best through spring, classic in a clear miso-based clam soup.
A tart, thick-skinned citrus reaching its season now, a milder relative of natsumikan.
One of the earliest foraged greens of the year, gathered along sunny field edges and riverbanks — traditionally simmered or added to a savory egg dish after the tougher outer sheaths are stripped off.
Still at its best through this stretch of the calendar.
Nekoyanagi's soft, silvery catkins appear along riverbanks and other damp ground right in step with this kō's own subject — one of the most direct visual matches anywhere in the calendar between a kō's stated meaning and what's actually visible outdoors at the time.
Usui is traditionally considered the most auspicious time to bring out hina-ningyō ahead of March 3rd's Hinamatsuri, on the belief that doing so brings the household good fortune in marriage. The connection runs back to the custom's own origin: hina dolls descend from 流し雛 (nagashibina), paper or straw figures once used to absorb a person's misfortune before being set adrift on a river — since the whole custom is bound up with water and purification to begin with, displaying the dolls right as Usui's rain and thaw arrive was considered a fitting, well-matched start to the season.
"The sun's warmth reaches the ground, snow and ice melt, and become rainwater." — The Edo-period almanac 暦便覧 (Koyomi Binran, 1787) explaining Usui's name in its own words — one of the clearest surviving statements of what a sekki name was actually meant to describe, written for ordinary almanac readers rather than court scholars.
脉 (myaku) is an older form of 脈, meaning "pulse" or "vein" — its use here to describe soil is a deliberate small metaphor, treating the ground as something with its own circulation rather than as inert material simply sitting there.
Usui is the traditionally favored window to begin — no need to wait until closer to March 3rd itself.
They're easy to miss at a glance, low and thin against bare soil — worth crouching down to actually look.
They're fibrous and unpleasant to eat — pinch and pull them off along the stem before simmering or adding to egg.
This kō's name is literal — precipitation genuinely shifts from snow to rain across most of the country around now.
There's a real difference between snow melting into a puddle that runs off and disappears, and rain soaking down into ground that goes on to hold and use it — the second version is what this kō is actually naming, water becoming part of what it's landed on rather than just passing across the surface. What's something recently that you let properly sink in and change you, instead of letting it evaporate the moment it arrived?