A single Koshu grape, whole, coated in sugar syrup. That is the entire confection.

Several accounts of its origin circulate, and what is striking is that they all say more or less the same thing, with the same accident at the center of them. A confectioner was boiling sugar. A grape fell in. Picked out and left, the syrup on it cooled and set to a pale white shell, and whoever tried it thought it good enough to sell.

The dating is less casual than that story suggests. A Kofu shopping guide published toward the end of the Edo period records several confectioners selling it, and it appears on a sugoroku board of famous places in Kai as gokusei tsuki no shizuku, finest moon-drops. It was already known by then.

The method now is precise. Sugar and water are heated to between a hundred and twelve and a hundred and fourteen degrees, cooled, and worked into fondant. Each grape is held by the stem with tweezers and passed through it. The Koshu grape suits this because its skin is thick enough to survive hot syrup and it carries enough acidity to stand up to the sugar. It can only be made while the grapes exist, from late September to December, or in some workshops as far as the following March. A few months a year, and then nothing.