A method implemented by a transmission device to communicate with multiple reception devices (10-2, 10-3,..., 10-n) that respectively share a drawing area with the transmission device, wherein the transmission device transmits to the multiple reception devices (10-2, 10-3,..., 10-n) vector-data ink data representative of traces of input operation detected by an input sensor of the transmission device, the method comprising: an ink data generation step that comprises: continuously inputting pen event data (INPUT 1) generated according to movement of a pointer, and generating fragmented data of a stroke object, wherein the stroke object contains multiple point objects (Point_i,..., Point_n) to represent a trace of said movement of the pointer, the fragmented data being generated per defined unit T, and generating a drawing style object, which defines a rendering configuration of said trace of the stroke object based on context information (INPUT 2), at a pen down time corresponding to generation of the pen event data at a beginning point of said trace; a message formation step that comprises: generating a first message that includes the drawing style object, and generating one or more second messages subsequent to the first message, the one or more second messages including the fragmented data; and a transmission step of transmitting the first message and the one or more second messages in sequence according to a defined communications protocol. an ink data generation step that comprises: continuously inputting pen event data (INPUT 1) generated according to movement of a pointer, and generating fragmented data of a stroke object, wherein the stroke object contains multiple point objects (Point_i,..., Point_n) to represent a trace of said movement of the pointer, the fragmented data being generated per defined unit T, and generating a drawing style object, which defines a rendering configuration of said trace of the stroke object based on context information (INPUT 2), at a pen down time corresponding to generation of the pen event data at a beginning point of said trace; continuously inputting pen event data (INPUT 1) generated according to movement of a pointer, and generating fragmented data of a stroke object, wherein the stroke object contains multiple point objects (Point_i,..., Point_n) to represent a trace of said movement of the pointer, the fragmented data being generated per defined unit T, and generating a drawing style object, which defines a rendering configuration of said trace of the stroke object based on context information (INPUT 2), at a pen down time corresponding to generation of the pen event data at a beginning point of said trace; a message formation step that comprises: generating a first message that includes the drawing style object, and generating one or more second messages subsequent to the first message, the one or more second messages including the fragmented data; and generating a first message that includes the drawing style object, and generating one or more second messages subsequent to the first message, the one or more second messages including the fragmented data; and a transmission step of transmitting the first message and the one or more second messages in sequence according to a defined communications protocol.