The proliferation of dollar-denominated stablecoins challenges national monetary sovereignty, necessitating strategic responses. This paper advocates for a strategically designed KRW-based stablecoin to protect Korea's monetary sovereignty and bolster its role in the digital economy. A four-pillar institutional foundation is proposed: first, a flexible regulatory policy ensuring user trust and competitive ease of access; second, issuance discipline for purchasing power stability and fiscal soundness; third, a credible, diversified reserve asset strategy, including Bitcoin, to build international trust; and fourth, diverse use cases amplified by an expanded issuer scope, including technology firms, to leverage network effects for widespread adoption. Implementing this framework aims to counter currency substitution threats and establish the KRW stablecoin as a key digital monetary instrument, enabling Korea to proactively shape its monetary future.