In his book 'Chinese jades from Han to Ch'ing', the renowned jade expert professor James C.Y. Watt writes that 'knuckle-bones' like this were probably used as pendants or toggles. The astragal, a small bone from the ankle joint of a sheep is one of the earliest forms of dice and was used continuously as such from the Liao period onwards for gambling. Astragals made of jade are all perforated for suspension. According to professor Watt the production of jade astragals seems only to have taken place during the Liao (907 - 1125AD) and Jin period (1115 - 1234AD). This astragal was added to the collection in 1986 and came from Hong Kong. Length 3.5 cm. Width 1.7 cm. Height 2.5 cm. Weight 25.6 grams.