1/3 cup (80ml) white rice vinegar
3 tablespoons Korean chili pepper paste (gochujang)
1 tablespoon very-finely minced garlic
2 tablespoons coarse Korean chili powder (gokchu garu)
1/2 tablespoon very-finely minced fresh ginger
4 scallions, sliced in 2-inch (5cm) batons, including the green part
Remove the tough outer leaves of the cabbage and slice it lengthwise in half. Remove the core.
Cut the cabbage into 2-inch (5cm) pieces. Toss the cabbage with the salt in a large bowl, then transfer it to a non-reactive colander. Set a plate on top then weigh it down with something heavy for 24 hours.
Mix together the vinegar, chili paste, garlic, chili powder, and ginger in a large, non-reactive bowl. Let this stand overnight.
Add the cabbage in handfuls to the marinade, taking small bunches at the time and squeezing them of any excess water before adding them to the marinade. Mix the cabbage with the marinade, adding the scallions as well.
Pack into a jar, cover tightly, and let stand at room temperature for 48 hours, then chill for 4 days before serving.