Firms need to choose a competitive technology position relative to the choices of their competitors. Therefore, firms change their technological similarity with their competitors through differentiation and learning. Although many studies on similarity have been accumulated, most focus on knowledge spillover among similar industries or firms. Therefore, we propose a method for decomposing the direction of technology accumulation into differentiation and learning using the case of fast-growing Chinese robotics firms. We also show that as these firms have closed the gap with a Japanese first-mover firm’s technology position, they also have begun to accumulate their own technologies. In other words, the accumulation of basic technologies for a business can be a precondition for the accumulation of proprietary technologies. A firm’s technology position as its technology structure can show how new industries emerge and industrial structure changes at the firm level.