Bitter melon or bitter gourd. (Momordica charantia) ゴーヤー.
My favorite Okinawan vegetable is the goya, a very bitter gourd that looks like a grotesque, extra knobbly cucumber.
[Sliced goya. Photo Ad Blankestijn]
Goya can be eaten in salads, made into tempura, but the most common way is to use it in a stir-fried dish called goya-champuru. What is bitter, is good for you, so goya is thought to be the secret behind the Okinawans’ famous longevity.