The Liangzhu trident and the other two Spring period jade masks have the same motif of deity which is the main motif of Liangzhu Culture. In this case, when we appraise these three jades, we should not just appraise them individually. We should take into account the value of these jades which are the evidence of the heritage of the Liangzhu deity motif from the Liangzhu Culture transcend into the Spring Autumn Period. In other words, we should view the object from system point of view rather than from the view of a single object. This is similar to the idea of stamp collection, you are considering the value of whole set of stamps rather than individual piece of stamps.