Cut the cabbage into quarters through the core so the leaves stay attached at the base.

Dissolve half the salt in the water to make a brine. Soak the cabbage quarters in the brine for 1 hour, then lift them out and rub the remaining salt by hand between the thicker white ribs of every leaf.

Let the salted cabbage sit for 1 to 2 hours more, turning it once, until the thick stem end bends without snapping like a fresh leaf would.

Rinse each quarter three times in cold water to remove excess salt, then stand it in a colander to drain for at least 30 minutes.

Whisk the rice flour into the water and simmer 3 to 4 minutes, stirring, until it thickens into a thin, glossy porridge. Cool it before using.

Stir the cooled porridge together with the gochugaru, fish sauce, salted shrimp, grated pear, onion, garlic, and ginger into a thick, spreadable paste.

Fold the radish and garlic chives into the paste.

Wearing gloves, pull each cabbage leaf back gently and spread the paste between every layer, from the core outward, until the whole quarter is coated inside and out.

Fold each seasoned quarter into a compact bundle and pack it tightly into a clean jar or container, pressing down so no air pockets remain and the kimchi's own liquid rises above the solids.

Leave the sealed container at room temperature for 1 to 2 days, until small bubbles appear at the edges, then move it to the refrigerator.