Recommended bowl: Double egg yolks

Yoroiya is an old school-style shop in the center of Asakusa, open since 1991. The soup is a light-clear broth made from chickens, pork, gyokai and vegetables, with both shoyu, shio and tsukemen also available. The gyoza are handmade every morning from scratch. What makes this shop really unique though is that each of the egg toppings comes from an egg containing twins, so each egg has a double yolk. The eggs are delivered daily from a farm near Mount Iwate in Iwate Prefecture. How can they tell that the eggs will have a double yolk? Apparently the chicken farmers can judge just by looking at the size.