The seisai is a variety said to have come from Chongqing in China in 1904. Yamagata brought seed in from Nara four years later, in 1908, and trialed it at the prefectural agricultural station. It proved better than the pickling greens already in use, and cultivation began in the Murayama district.

A single plant weighs around five hundred grams and stands seventy to eighty centimeters. Broad leaves, thick stems, a crisp bite, and a distinct heat to it.

The pickling happens in two stages. The greens are dried briefly in the sun and salted, and left three days.

Then they are washed, and a liquid of soy sauce, sugar, and sake, heated to just short of boiling and cooled, is poured over them with shochu added, and they sit for another week. Harvest runs from late October into mid-November, and the pickle is eaten through to early spring. By then it has gone amber and turned sour, and at that point it is chopped and fried down into something else. The plant that arrived had stems that twisted; growers selected for individuals that did not, and that selection is what the Yamagata variety is. It gets a second life after it has gone past its first.