There are many different brand names, manufacturing dates, patterns and legends under the "Blue Willow china" umbrella. Identifying any particular type of Blue Willow china, whether antique or current, is a matter of knowing what to look for in terms of its traditional features, and a process of elimination thereafter. Begin by finding out as much as possible about every aspect of Blue Willow china.
Research the origin of Blue Willow china (References 1) to know who produced the earliest versions. The British potter, Thomas Turner of Caughley China (later Coalport) developed the original pattern engraved by Thomas Minton in 1780. Subsequently, Minton joined Spode Pottery which also manufactured Blue Willow and later made his own at Minton Pottery. Adams, Davenport, Royal Worcester, and Wedgwood made Blue Willow china due to popular demand.
Look for variations in the Blue Willow pattern (References 2). The most popular patterns usually include several of these elements: two birds (doves in some versions, lovebirds in others) circling overhead, a willow tree, an apple tree, a pagoda/residence, a bridge with three people on it, a boat in the water with a person in it, a latticework fence and a border of butterflies. Apparently the original version of the Blue Willow pattern had no birds, bridge or apple tree,
Explore the various versions of the Willow Tree legend, because they explain the differences in the patterns (References 3). The basic legend is of two star-crossed lovers, Koong-se, the daughter of a Mandarin, and Chang, his secretary. They run away together much to the fury of the Mandarin, who wishes Koong-se to marry a wealthy suitor. In some versions, the gods take pity on the young lovers, and turn them into birds. In other versions, Chang is killed, and Koong-se commits suicide in grief. The willow tree is central to the original pattern, but the apple tree, for example, was probably an English addition.
Look at online antiques or auction sites for Blue Willow china made by the master potters. Most reputable sellers will include comprehensive descriptions and photographs, and provide further information on request. Ask about maker's marks if they are not shown in photos or described in the accompanying text.
Compare notes with collectors of Blue Willow china, through their organisation called "International Willow Collectors" (Resources 2). Its aim is to promote greater knowledge about Blue Willow china and to foster communication among collectors.
Find out about the wide array of items manufactured in Blue Willow patterns over the years, including dinner and tea services, platters, canisters, glassware, and lamps (Resources 1). Some manufacturers continue to produce Blue Willow china. Be aware that some manufacturers have produced the Blue Willow pattern in other colours, such as red.