Abstract:     For latecomer firms, core technology and complementary assets represent two different catch-up strategies, however, latecomer firms often face the dilemma of how to choose and balance the two strategies as relatively resources scarce. Different from the initial catch-up in the secondary innovation stage, in the process of beyond catch-up from the secondary innovation to the original innovation, latecomer firms begin to approach and challenge the industry leaders，which need to innovate in a constantly changing competitive environment where there are few opportunities for direct imitation. However, there is a lack of research on the evolution mechanism of the post-secondary innovation to the original innovation.
    Additionally, the existing research on the relationship between core technology and complementary assets mainly focus on incumbents in developed economies, lacking a catch-up perspective based on latecomers. In particular, the interaction between core technology and complementary assets is still unclear in the context of new technological change in which Chinese latecomer firms are in the beyond catch-up phase. Therefore, the research question of this paper is how to choose and balance the two strategies of core technology and complementary assets for latecomer firms in the dynamic process of beyond catch-up from the secondary innovation to the original innovation?
    The research question in this paper involve the detailed process of "how", and the case study is suitable for answering questions like "how" and "why", so the longitudinal single case study method is chosen. This paper chooses the beyond catch-up process of Haitian Plastic Machine Group CO., LTD (hereinafter abbreviated as "Haitian") in the field of all-electric injection molding machine technology as the object of the case study. In this research, a variety of different data collection methods, such as personnel interview, literature materials and archival records, are adopted to ensure that the research data were mutually supplemented and cross-verified through diversified research information and data sources, so as to ensure the reliability and validity of the research. The data analysis process of this paper also follows the process of inductive case studies. 
    Through the case study of Haitian′s catch-up in the field of all-electric injection molding machine technology from 2001 to 2017, this paper finds that in the secondary innovation stage, latecomer firms have experienced the transformation of catch-up strategy from core technology dominance to complementary asset dominance, which not only breaks through the core technology, but also gains market revenue. In the original innovation stage, latecomer firms adopt the strategy of pursuing both core technology and complementary assets, that is, on the one hand, they carry out core technology research and development by capturing the windows of opportunity brought by changes in market demand; on the other hand, they gain innovation benefits through complementary assets, which ultimately promotes the joint improvement of their technological capabilities and market performance. Therefore, from the perspective of organizational ambidexterity, in the dynamic process of beyond catch-up from the post-secondary innovation to the original innovation, the catch-up strategy of latecomer firms has undergone the evolution from the punctuated balance of core technology and complementary assets to the ambidextrous balance in which both are equally valued.
    This study has theoretical contributions in the following three aspects. First of all, this study deepens our understanding of the dynamics of latecomers catch-up. In the dynamic process of beyond catch-up from the post-secondary innovation to the original innovation, the core technology and complementary assets show the characteristics of interactive evolution, realizing dynamic alternations in the dimension of time and space, following the evolution process from punctuated balance mode to the ambidextrous balance mode, and finally enabling the latecomers to achieve beyond catch-up. Therefore, this discovery reveals the beyond catch-up mechanism of latecomer firms from the secondary innovation to the original innovation, deepens our understanding of beyond catch-up.
    Secondly, this study also enriches the theory of complementary assets. From the perspective of catch-up of latecomer firms, this paper investigates the leading role and evolution characteristics of complementary asset construction and core technology R&D in latecomers′ catch-up, and finds that from the secondary innovation to the original innovation, the complementary asset construction and core technology research and development follow the transformation from punctuated balance to ambidextrous balance. This conclusion enriches the research situation of complementary assets from the perspective of catch-up and helps to further understand the dynamic relationship between complementary assets and technology R&D.
    Finally, this study also expands the ambidexterity theory. This paper finds that the strategic balance between complementary assets and technology R&D of latecomers belongs to the cross-domain balance between market and technology, that is, the ambidextrous balance can be realized through cross-domain. Further, the realization mode of enterprise ambidextrous balance is dynamic changing, from the secondary innovation to original innovation, latecomer firms balance explorative and exploitative activities through different modes, in the secondary innovation stage, punctuated balance is achieved; in the original innovation stage, ambidextrous balance is achieved. The discovery that the ambidextrous pattern evolves from sequence to synchronic in the process of beyond catch-up deepens our understanding of the dynamics of organizational ambidextrous balance.
    This paper also provides relevant empirical enlightenment for the latecomer firms at the stage of beyond catch-up. First, latecomer firms should build up their R&D capabilities quickly at the beyond catch-up phase. They should be highly sensitive to the windows of opportunity of emerging technologies, and cut into the field of emerging technologies as quickly as possible to build the R&D capacity of new technologies, and timely build key proprietary complementary assets to accelerate the evolution cycle of secondary innovation and realize the evolution of original innovation. Second, latecomer firms should continue to develop competitive manufacturing capabilities. If a series of manufacturing complementary assets associated with mature technologies are also valuable for alternative emerging technologies, latecomer firms can combine global management skills to develop competitive manufacturing complementary assets and provide customized products or services for customers. Finally, latecomer firms should fully recognize the strategic significance of market-specific complementary assets. Market-specific complementary assets, such as developing and mastering new brands, foreign distribution and service channels, can enable latecomer firms to grasp the channels and capabilities to provide their own products and services to final users and gain the opportunity to learn from leading users. 

Key words: core technology, complementary assets, secondary innovation, beyond catch-up, ambidextrous balance