In this paper, we propose a new distributed event delivery method for MMORPG (Massively Multiplayer Online Role Playing Games). In our method, the whole game space is divided into multiple sub spaces with the same size and some player nodes are selected as responsible nodes to deliver game events occurring in their responsible sub spaces. Our method includes (1) a load balancing mechanism which allows each responsible node for the crowded sub space to dynamically construct a tree of multiple nodes and deliver events along the tree to reduce event forwarding overhead per node, (2) a technique to reduce end-to-end event delivery delay by dynamically replacing nodes in the tree, and (3) a technique to efficiently and seamlessly switch sub spaces to be observed while each player’s view moves around in the game space. Through experiments, we show that our method achieves practical performance for MMORPG. Categories and Subject Descriptors C.2.4 [Distributed Systems]: Distributed applicat...