In America we prefer such varieties of Chinese cabbage as Chihli, which forms a long, slender, nearly cylindrical head that is relatively solid and weighs one to two pounds when trimmed. I was amazed at the enormously thick, squat types, weighing ten to twelve pounds, that the Japanese prefer. The variety sold in this country as Pak Choy is not Chinese cabbage, strictly speaking, but Chinese mustard. Therefore, when cooked they are lacking in distinctive flavor. They are most commonly eaten raw as salads rather than cooked as potherbs.
Indian mustard is much better for cooking as greens.
Chinese cabbage and Chinese mustard are annual plants that grow best in a mild climate. If they are planted at such a season that they encounter very hot weather, they will shoot to seed without forming the attractive and productive kind of plant that is desired. The varieties that we grow have been introduced from the Orient.