In a large pan, bring salted water to the boil. Add the pasta, stirring constantly in the beginning to prevent it from sticking togehter. Cook until al dente, about 8 minutes.
Meanwhile, heat the olive oil in a large frying pan. Add a dollop of butter. When almost smoking, add garlics and perilla and saute until soft and translucent, about 3 or 4 minutes, being careful not to burn the garlic.
Add the calms and wine and salt. Cover and simmer for 6 to 8 minutes or until most clams have opened.
Drain the pasta in a colander. Do not rinse it with water- this will remove the natural starches. Place the pasta into the clam pan and mix thorougly. Check seasoning.
Pour the pasta into the large serving bowl. Zest balck pepper over the dish. Garnish with remaining perilla. Serve immediately.