Abstract:

Blockchain-based traceability technology has contributed to the widespread adoption of formal supply chain quality information systems. Through the quality blockchain， suppliers are able to decide how much quality information to share and with whom， thereby alleviating their concerns about information leakage and loss of competitive advantage， which has significant implications for their pricing decisions and performance. However， the majority of existing studies have focused solely on the binary quality information sharing decision， sharing or non-sharing， instead of flexible decision-making. Furthermore， it needs to discuss the impact of the most important factors in the market， namely quality and price competition， on the supply chain information-related decisions.It is discussed how suppliers make quality information sharing decisions in the competitive environment， how quality information sharing level affect the decision-making and performance of the supply chain players， how quality and price competition intensity affect quality information sharing decisions and supply chain profit， and whether suppliers should share quality information horizontally with their competitors.A multi-stage game model of quality and price competition is established for two suppliers participating and their common retailer in the same quality blockchain under a competitive environment， and the optimal vertical quality information sharing decision， supply chain pricing decision and benefits of all parties are analyzed under three horizontal quality information sharing strategies of non-sharing， two-way sharing and unilateral sharing through blockchain authorization. Then the influence of quality and price competition intensity and equilibrium deviation behaviors is discussed. Finally， a robust numerical example is used to verify the effectiveness of the model and management implications are presented.It is found that （i） Regardless of the horizontal quality information sharing strategy adopted by the competing suppliers， vertical quality information sharing from either supplier can always yield nonnegative direct or spillover effects to the information recipients. This reflects the value of quality information， emphasizing the need for supply chain enterprises to prioritize and take the lead in quality blockchain information sharing and authorization management. （ii） The intensification of quality competition encourages suppliers to improve their quality information sharing level， which benefits each supply chain player， while the intensification of price competition inhibits suppliers' input in quality information， which harms any supplier's profit and the spillover effect obtained by the retailer， but helps the retailer obtain a higher certain profit. Therefore， for suppliers， keeping sufficient quality advantage is an effective way to avoid being hurt by price competition； For the retailer， it is more beneficial when price competition is intense while quality is relatively stable， such as for daily consumer goods， and more beneficial when price competition is weak while quality fluctuation is large， such as for high-end fresh food market. （iii） Suppliers' vertical quality information sharing decisions are influenced by their own strategies， and in turn by their competitors' horizontal quality information sharing strategies. When quality competition is weak， the optimal strategy of any supplier is horizontal sharing. When the quality competition is strong， the optimal strategy is horizontal non-sharing. （iv） When price competition is weak while quality competition is relatively strong， suppliers have the incentive to share quality information with each other to mitigate quality competition and reduce quality information inputs， but this may hurt the profits of the retailer and the whole supply chain， and the sharing level of supply chain quality information. From the standpoint of the supply chain， it is necessary to prevent the suppliers from conspiring to monopolize the supply.This study provides theoretical basis and practical guidance for supply chain enterprises to decide quality information input and product price when facing competitive products， and to use quality blockchain for information authorization and management. It also has reference value for the retail to improve marketing management of competitive products. In the future， the research can be extended to more supply chain structures， decision influencing factors and empirical research.

Key words: quality blockchain, supply chain, information sharing, game theory