Step 1

Divide ginger equally 4 ways and place into 4 small bowls.

Step 2

Combine Chinkiang and rice vinegars with sugar in a small pan. Warm over low heat, stirring occasionally until sugar dissolves. Let cool. Meanwhile, bring 2 inches of water to a boil in a wok or a large pot. Once cool, divide vinegar sauce into the 4 bowls with ginger.

Step 3

Clean crabs with a stiff-bristled brush under running water. If using a wok, place clean crabs shell-side down into two large bamboo steamer baskets, one over the other, and fit with lid. If using a Western-style pot, place crabs shell-side down in a standard steamer basket. Place steamer baskets over boiling water, cover if using a Western-style pot, and steam until crabs are cooked through, 8 to 10 minutes.

Step 4

Serve crabs warm with vinegar and ginger dipping sauce.